well my mod doom the mercenaries have a bug, when the player die, not display the death animation and still on the spawn state after the death, this bug also appear on my ultimate super doom3, and much worse happen the same on gzdoom, so that explain is not only a zandronum problem, i guess i founded the problem:
death:
xxx a ...
blah bla...
.
.
tnt1 a -1
stop
the problem was the last line, tnt1 a -1 i changed for another sprite and the problem was solved, but is very strange put a non sprite line or another missing sprite cause this bug.