Linedef 5885 has a Thing_Spawn special that's meant to spawn a few Flesh Spawn (heh) as the player barges into the room. This should be changed to call a script that uses SpawnSpot, since the Fleshspawn's SpawnID is no longer valid. Better to use the named one for consistency rather than re-add the SpawnID, I think.

[EDIT] Fixed as of this version.