Question about Icon of Sin behavior

[SuperGiantNinjaYeti]

Hello everyone. I'm new here, so apologies in advance if this isn't quite the correct subforum for this question.
I recently made a vanilla level in the map01 slot, with an icon of sin setup except the spawn spots are arranged in a line to make the spawned monsters get stuck with each other, forming a destructible wall of sorts.

Since GZDoom lets monsters spawned by the icon of sin telefrag in any map slot (as opposed to only map30), and stacked monsters can still move instead of getting stuck in place, my level doesn't work as intended in GZDoom. I don't mind this too much, as it is still playable, just different, and GZDoom wasn't my target port to begin with, but out of curiosity I checked the compatibility options and couldn't find anything about these two differences.

I also checked the mapinfo properties but the closest thing I found was allowing general monster telefragging, the opposite of what I want.
I'm pretty sure a "fix" could be done with zscript. I did manage to prevent the telefragging with a SpawnShot replacement, but then the monsters don't remain stuck. Before delving further into that, however, I'd like to make sure I'm not overlooking a simpler solution.

So, just to be absolutely sure I didn't miss anything, I'd like to ask: is there a flag, some other lump or something to directly revert those two changes (icon of sin telefraging in any map and stacked monsters being able to disperse)?