Boss intangible after first hit

[Joat]

Here is the coding for a custom boss I am making. The problem with this boss is that, after the first hit, it becomes intangible. It still spawns enemies as it should, but it is impossible to hit.

Thing 331
MAPTHINGNUM = 2004
SPAWNSTATE = 1809
SPAWNHEALTH = 10
SEESTATE = 1815
SEESOUND = 0
REACTIONTIME = 8
ATTACKSOUND = 0
PAINSTATE = 1823
PAINCHANCE = 200
PAINSOUND = 46
MELEESTATE = 1815
MISSILESTATE = 1815
DEATHSTATE = 0
DEATHSOUND = 0
XDEATHSTATE = 0
SPEED = 4
RADIUS = 1572864
HEIGHT = 3407872
MASS = 0
DAMAGE = 20
ACTIVESOUND = 227
RAISESTATE = 1810
FLAGS = 645

FRAME 1809
SPRITENUMBER = 246
SPRITESUBNUMBER = 0
DURATION = 10
NEXT = 1809
ACTION None
VAR1 = 1
VAR2 = 1

FRAME 1810
SPRITENUMBER = 246
SPRITESUBNUMBER = 1
DURATION = 10
NEXT = 1811
ACTION None
VAR1 = 0
VAR2 = 0

FRAME 1811
SPRITENUMBER = 246
SPRITESUBNUMBER = 2
DURATION = 10
NEXT = 1812
ACTION None
VAR1 = 0
VAR2 = 0

FRAME 1812
SPRITENUMBER = 246
SPRITESUBNUMBER = 3
DURATION = 10
NEXT = 1813
ACTION A_SpawnObjectRelative
VAR1 = 0
VAR2 = 320

FRAME 1813
SPRITENUMBER = 246
SPRITESUBNUMBER = 2
DURATION = 10
NEXT = 1814
ACTION None
VAR1 = 0
VAR2 = 0

FRAME 1814
SPRITENUMBER = 246
SPRITESUBNUMBER = 1
DURATION = 10
NEXT = 1815
ACTION None
VAR1 = 0
VAR2 = 0

FRAME 1815
SPRITENUMBER = 246
SPRITESUBNUMBER = 0
DURATION = 35
NEXT = 0
ACTION A_RandomState
VAR1 = 1810
VAR2 = 1816

FRAME 1816
SPRITENUMBER = 246
SPRITESUBNUMBER = 4
DURATION = 35
NEXT = 1817
ACTION None
VAR1 = 0
VAR2 = 0

FRAME 1817
SPRITENUMBER = 246
SPRITESUBNUMBER = 5
DURATION = 35
NEXT = 1818
ACTION None
VAR1 = 0
VAR2 = 0

FRAME 1818
SPRITENUMBER = 246
SPRITESUBNUMBER = 6
DURATION = 35
NEXT = 1819
ACTION None
VAR1 = 0
VAR2 = 0

FRAME 1819
SPRITENUMBER = 246
SPRITESUBNUMBER = 7
DURATION = 35
NEXT = 1820
ACTION A_SpawnObjectRelative
VAR1 = 0
VAR2 = 320

FRAME 1820
SPRITENUMBER = 246
SPRITESUBNUMBER = 6
DURATION = 35
NEXT = 1821
ACTION None
VAR1 = 0
VAR2 = 0

FRAME 1821
SPRITENUMBER = 246
SPRITESUBNUMBER = 5
DURATION = 35
NEXT = 1822
ACTION None
VAR1 = 0
VAR2 = 0

FRAME 1822
SPRITENUMBER = 246
SPRITESUBNUMBER = 4
DURATION = 35
NEXT = 1815
ACTION None
VAR1 = 0
VAR2 = 0

FRAME 1823
SPRITENUMBER = 246
SPRITESUBNUMBER = 8
DURATION = 35
NEXT = 1815
ACTION A_Pain
VAR1 = 0
VAR2 = 0

Also, yes, I am aware that there are a few subtle flaws (for example, no death state), but this is, after all, a boss-in-progress, so things will be missing. Please only point out the flaws that could be responsible for the intangible boss.

EDIT: After much experimentation, I have found the solution myself. The painstate apparently needs to redirect to the spawnstate in order for the boss to be open for attack again. It makes absolutely no sense, but oh well.