Crumbling FOF types are broken

Just like Floating, Bobbing specials, the Crumbling FOF thinkers break when applied to multiple target sectors, in this case much more dramatically. From my experience, if a Crumbling FOF applies to two control sectors, the crumbling noise is diminished. If it applies to even more sectors, it doesn't crumble at all...it just sinks slowly.

Why are you tagging to more than one sector?

It's hard to explain, but making multiple sectors crumble at once is important to this one specific type of gimmick.

SRB2 Community: "Why not just use linedef executors instead?"

Fawfulfan: "Again, hard to explain, but the gimmick really only works with Linedef Type 176. Just take my word for it."

As for the sound tidbit, this is because the sound is set to originate from the center of the affected sector. If the "affected sector" is several sectors or just a single one split across various points in the map, then this "center" wil almost invariably end up outside the actual sector, possibly even outside the map. The same thing happens with crushers, and I had to actively split some sectors into identical, smaller ones so the sound could actually be heard.