Moved Clients joining a NiGHTS stage mid-game crashes the game for them.

[Maril]

Joining a server that's in a NiGHTS stage will shortly after crash SRB2, resulting in a SIGABRT, or SIGSEGV depending on the case.
I have attached part of my crash-log.txt below, and this was tested with and without add-ons, and with clients on different platforms (Windows, Linux, etc)

------------------------ An error occurred within SRB2! Send this stack trace to someone who can help! Time of crash: Sat, 11 Nov 2023 05:00:41 -0600 Cause: Segmentation fault Backtrace: /home/speccy/SRB2/bin/lsdl2srb2.debug(+0x86f4b)[0x5555555daf4b] /home/speccy/SRB2/bin/lsdl2srb2.debug(+0x8707c)[0x5555555db07c] /lib/x86_64-linux-gnu/libc.so.6(+0x42520)[0x7ffff77f8520] /home/speccy/SRB2/bin/lsdl2srb2.debug(P_TouchSpecialThing+0x1281)[0x5555556e1701] /home/speccy/SRB2/bin/lsdl2srb2.debug(+0x198292)[0x5555556ec292] /home/speccy/SRB2/bin/lsdl2srb2.debug(P_BlockThingsIterator+0x87)[0x5555556f07a7] /home/speccy/SRB2/bin/lsdl2srb2.debug(P_CheckPosition+0x538)[0x5555556e6318] /home/speccy/SRB2/bin/lsdl2srb2.debug(+0x1ad606)[0x555555701606] /home/speccy/SRB2/bin/lsdl2srb2.debug(+0x1af990)[0x555555703990] /home/speccy/SRB2/bin/lsdl2srb2.debug(P_MobjThinker+0x1ce)[0x555555709d1e] /home/speccy/SRB2/bin/lsdl2srb2.debug(P_Ticker+0x81e)[0x55555574be6e] /home/speccy/SRB2/bin/lsdl2srb2.debug(G_Ticker+0xfbe)[0x555555661bfe] /home/speccy/SRB2/bin/lsdl2srb2.debug(TryRunTics+0x1d4)[0x55555561dfb4] /home/speccy/SRB2/bin/lsdl2srb2.debug(D_SRB2Loop+0x9d7)[0x55555560fc07] /home/speccy/SRB2/bin/lsdl2srb2.debug(main+0x7c)[0x5555555da3ac] /lib/x86_64-linux-gnu/libc.so.6(+0x29d90)[0x7ffff77dfd90] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0x80)[0x7ffff77dfe40] /home/speccy/SRB2/bin/lsdl2srb2.debug(_start+0x25)[0x5555555da5d5] ------------------------ An error occurred within SRB2! Send this stack trace to someone who can help! Time of crash: Sat, 11 Nov 2023 05:03:00 -0600 Cause: Segmentation fault Backtrace: /home/speccy/SRB2/bin/lsdl2srb2.debug(+0x86f4b)[0x5555555daf4b] /home/speccy/SRB2/bin/lsdl2srb2.debug(+0x8707c)[0x5555555db07c] /lib/x86_64-linux-gnu/libc.so.6(+0x42520)[0x7ffff77f8520] /home/speccy/SRB2/bin/lsdl2srb2.debug(P_TouchSpecialThing+0x1281)[0x5555556e1701] /home/speccy/SRB2/bin/lsdl2srb2.debug(+0x198292)[0x5555556ec292] /home/speccy/SRB2/bin/lsdl2srb2.debug(P_BlockThingsIterator+0x87)[0x5555556f07a7] /home/speccy/SRB2/bin/lsdl2srb2.debug(P_CheckPosition+0x538)[0x5555556e6318] /home/speccy/SRB2/bin/lsdl2srb2.debug(+0x1ad606)[0x555555701606] /home/speccy/SRB2/bin/lsdl2srb2.debug(+0x1af990)[0x555555703990] /home/speccy/SRB2/bin/lsdl2srb2.debug(P_MobjThinker+0x1ce)[0x555555709d1e] /home/speccy/SRB2/bin/lsdl2srb2.debug(P_Ticker+0x81e)[0x55555574be6e] /home/speccy/SRB2/bin/lsdl2srb2.debug(G_Ticker+0xfbe)[0x555555661bfe] /home/speccy/SRB2/bin/lsdl2srb2.debug(TryRunTics+0x1d4)[0x55555561dfb4] /home/speccy/SRB2/bin/lsdl2srb2.debug(D_SRB2Loop+0x9d7)[0x55555560fc07] /home/speccy/SRB2/bin/lsdl2srb2.debug(main+0x7c)[0x5555555da3ac] /lib/x86_64-linux-gnu/libc.so.6(+0x29d90)[0x7ffff77dfd90] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0x80)[0x7ffff77dfe40] /home/speccy/SRB2/bin/lsdl2srb2.debug(_start+0x25)[0x5555555da5d5] ------------------------ An error occurred within SRB2! Send this stack trace to someone who can help! Time of crash: Sat, 11 Nov 2023 05:21:09 -0600 Cause: Aborted Backtrace: /home/speccy/SRB2/bin/lsdl2srb2.debug(+0x86f4b)[0x5555555daf4b] /home/speccy/SRB2/bin/lsdl2srb2.debug(+0x8707c)[0x5555555db07c] /lib/x86_64-linux-gnu/libc.so.6(+0x42520)[0x7ffff77f8520] /lib/x86_64-linux-gnu/libc.so.6(pthread_kill+0x12c)[0x7ffff784ca7c] /lib/x86_64-linux-gnu/libc.so.6(raise+0x16)[0x7ffff77f8476] /lib/x86_64-linux-gnu/libc.so.6(abort+0xd3)[0x7ffff77de7f3] /lib/x86_64-linux-gnu/libc.so.6(+0x896f6)[0x7ffff783f6f6] /lib/x86_64-linux-gnu/libc.so.6(+0xa0d7c)[0x7ffff7856d7c] /lib/x86_64-linux-gnu/libc.so.6(+0xa2efc)[0x7ffff7858efc] /lib/x86_64-linux-gnu/libc.so.6(free+0x73)[0x7ffff785b4d3] /home/speccy/SRB2/bin/lsdl2srb2.debug(P_Ticker+0x81e)[0x55555574be6e] /home/speccy/SRB2/bin/lsdl2srb2.debug(G_Ticker+0xfbe)[0x555555661bfe] /home/speccy/SRB2/bin/lsdl2srb2.debug(TryRunTics+0x1d4)[0x55555561dfb4] /home/speccy/SRB2/bin/lsdl2srb2.debug(D_SRB2Loop+0x9d7)[0x55555560fc07] /home/speccy/SRB2/bin/lsdl2srb2.debug(main+0x7c)[0x5555555da3ac] /lib/x86_64-linux-gnu/libc.so.6(+0x29d90)[0x7ffff77dfd90] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0x80)[0x7ffff77dfe40] /home/speccy/SRB2/bin/lsdl2srb2.debug(_start+0x25)[0x5555555da5d5] ------------------------ An error occurred within SRB2! Send this stack trace to someone who can help! Time of crash: Sat, 11 Nov 2023 10:05:31 -0600 Cause: Aborted Backtrace: /home/speccy/SRB2/bin/lsdl2srb2.debug(+0x86f4b)[0x5555555daf4b] /home/speccy/SRB2/bin/lsdl2srb2.debug(+0x8707c)[0x5555555db07c] /lib/x86_64-linux-gnu/libc.so.6(+0x42520)[0x7ffff77f8520] /lib/x86_64-linux-gnu/libc.so.6(pthread_kill+0x12c)[0x7ffff784ca7c] /lib/x86_64-linux-gnu/libc.so.6(raise+0x16)[0x7ffff77f8476] /lib/x86_64-linux-gnu/libc.so.6(abort+0xd3)[0x7ffff77de7f3] /lib/x86_64-linux-gnu/libc.so.6(+0x896f6)[0x7ffff783f6f6] /lib/x86_64-linux-gnu/libc.so.6(+0xa0d7c)[0x7ffff7856d7c] /lib/x86_64-linux-gnu/libc.so.6(+0xa2efc)[0x7ffff7858efc] /lib/x86_64-linux-gnu/libc.so.6(free+0x73)[0x7ffff785b4d3] /home/speccy/SRB2/bin/lsdl2srb2.debug(P_Ticker+0x81e)[0x55555574be6e] /home/speccy/SRB2/bin/lsdl2srb2.debug(G_Ticker+0xfbe)[0x555555661bfe] /home/speccy/SRB2/bin/lsdl2srb2.debug(TryRunTics+0x1d4)[0x55555561dfb4] /home/speccy/SRB2/bin/lsdl2srb2.debug(D_SRB2Loop+0x9d7)[0x55555560fc07] /home/speccy/SRB2/bin/lsdl2srb2.debug(main+0x7c)[0x5555555da3ac] /lib/x86_64-linux-gnu/libc.so.6(+0x29d90)[0x7ffff77dfd90] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0x80)[0x7ffff77dfe40] /home/speccy/SRB2/bin/lsdl2srb2.debug(_start+0x25)[0x5555555da5d5] ------------------------ An error occurred within SRB2! Send this stack trace to someone who can help! Time of crash: Sat, 11 Nov 2023 10:23:01 -0600 Cause: Aborted Backtrace: ------------------------ An error occurred within SRB2! Send this stack trace to someone who can help! Time of crash: Sat, 11 Nov 2023 10:31:52 -0600 Cause: Segmentation fault Backtrace: /home/speccy/SRB2/bin/lsdl2srb2.debug(+0x86f4b)[0x5555555daf4b] /home/speccy/SRB2/bin/lsdl2srb2.debug(+0x8707c)[0x5555555db07c] /lib/x86_64-linux-gnu/libc.so.6(+0x42520)[0x7ffff77f8520] /home/speccy/SRB2/bin/lsdl2srb2.debug(P_TouchSpecialThing+0x1281)[0x5555556e1701] /home/speccy/SRB2/bin/lsdl2srb2.debug(+0x198292)[0x5555556ec292] /home/speccy/SRB2/bin/lsdl2srb2.debug(P_BlockThingsIterator+0x87)[0x5555556f07a7] /home/speccy/SRB2/bin/lsdl2srb2.debug(P_CheckPosition+0x538)[0x5555556e6318] /home/speccy/SRB2/bin/lsdl2srb2.debug(+0x1927e2)[0x5555556e67e2] /home/speccy/SRB2/bin/lsdl2srb2.debug(P_TryMove+0x47)[0x5555556e81d7] /home/speccy/SRB2/bin/lsdl2srb2.debug(P_XYMovement+0x2aa)[0x5555557006fa] /home/speccy/SRB2/bin/lsdl2srb2.debug(+0x1ad473)[0x555555701473] /home/speccy/SRB2/bin/lsdl2srb2.debug(+0x1af990)[0x555555703990] /home/speccy/SRB2/bin/lsdl2srb2.debug(P_MobjThinker+0x1ce)[0x555555709d1e] /home/speccy/SRB2/bin/lsdl2srb2.debug(P_Ticker+0x81e)[0x55555574be6e] /home/speccy/SRB2/bin/lsdl2srb2.debug(G_Ticker+0xfbe)[0x555555661bfe] /home/speccy/SRB2/bin/lsdl2srb2.debug(TryRunTics+0x1d4)[0x55555561dfb4] /home/speccy/SRB2/bin/lsdl2srb2.debug(D_SRB2Loop+0x9d7)[0x55555560fc07] /home/speccy/SRB2/bin/lsdl2srb2.debug(main+0x7c)[0x5555555da3ac] /lib/x86_64-linux-gnu/libc.so.6(+0x29d90)[0x7ffff77dfd90] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0x80)[0x7ffff77dfe40] /home/speccy/SRB2/bin/lsdl2srb2.debug(_start+0x25)[0x5555555da5d5] ------------------------ An error occurred within SRB2! Send this stack trace to someone who can help! Time of crash: Sat, 11 Nov 2023 10:43:32 -0600 Cause: Segmentation fault Backtrace: ./lsdl2srb2(+0x86f4b)[0x55de2ff09f4b] ./lsdl2srb2(+0x8707c)[0x55de2ff0a07c] /lib/x86_64-linux-gnu/libc.so.6(+0x42520)[0x7fb0acf9f520] ./lsdl2srb2(P_TouchSpecialThing+0x1281)[0x55de30010701] ./lsdl2srb2(+0x198292)[0x55de3001b292] ./lsdl2srb2(P_BlockThingsIterator+0x87)[0x55de3001f7a7] ./lsdl2srb2(P_CheckPosition+0x538)[0x55de30015318] ./lsdl2srb2(+0x1927e2)[0x55de300157e2] ./lsdl2srb2(P_TryMove+0x47)[0x55de300171d7] ./lsdl2srb2(P_XYMovement+0x2aa)[0x55de3002f6fa] ./lsdl2srb2(+0x1ad473)[0x55de30030473] ./lsdl2srb2(+0x1af990)[0x55de30032990] ./lsdl2srb2(P_MobjThinker+0x1ce)[0x55de30038d1e] ./lsdl2srb2(P_Ticker+0x81e)[0x55de3007ae6e] ./lsdl2srb2(G_Ticker+0xfbe)[0x55de2ff90bfe] ./lsdl2srb2(TryRunTics+0x1d4)[0x55de2ff4cfb4] ./lsdl2srb2(D_SRB2Loop+0x9d7)[0x55de2ff3ec07] ./lsdl2srb2(main+0x7c)[0x55de2ff093ac] /lib/x86_64-linux-gnu/libc.so.6(+0x29d90)[0x7fb0acf86d90] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0x80)[0x7fb0acf86e40] ./lsdl2srb2(_start+0x25)[0x55de2ff095d5]