PSX Doom monster placement doesn't work for smooshed(merged) wad

[litaniast]

It works well for standalone Ultimate Doom wad(including BFG edition and Unity port), but doesn't work for merged pk3 used wadsmoosh (https://jp.itch.io/wadsmoosh)
I used wadsmoosh 1.41 with those wads:
Ultimate Doom (original MS-DOS one, neither BFG edition nor Unity port)
Doom II (also original MS-DOS one)
TNT: Evilution (also original MS-DOS one, not Unity port)
The Plutonia Experiment (also original MS-DOS one)
Master Level for Doom II (original separated wads)
No Rest for the Wicked (from BFG edition)
Sewers, Betray (from extracted Xbox port. With them, wadsmoosh makes secret exit for those levels like xbox port)
Sigil (without addon soundtrack)
Sigil II (without addon soundtrack either)