Arg, well forget about it, I've turned off both the sound mods, but my last theory was correct; it has something to do with the Portal Gun. Weird. So, I'll just ask them instead, since you aren't the creator of that resource, my bad!

Now I might be annoying wtih this, but I want to add that, maybe it's a problem with the Portal Gun Resource Mod: https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=1605948111&searchtext=portal+gun
Because Serious Sam didn't had player-ingame-made portals, I'm theorizing if that may mess up with the range of the sounds.

But, I'm not at all familiar with Serious Engine's sound system, so I don't know myself. Maybe, if you first want to replicate the problem I'm describing, you may need the Portal Gun, again I've been going from one side of the map to another in the DLC to beat them as fast as I could, like going for the levers in the 1st DLC Level. Anyway, I hope I'm being clear with this.

Ah, P.S., however in that Video I did in April 2021, I did killed everything on sight instead of skipping stuff, so again, I may be mistaken in me being mistaken .

Mmh, I may be slightly mistaken, because this mod here, I was subscribed back in July 2019, and I don't ever recall hearing a problem when I did my last video on a Fusion-HD Mod in April, but the "HD Floor Material Sound Scheme Fixes", I just subscribed to it, so that MAY be it. However, it's to say these two were the only two sound Mods I was subscribed to.

I think the Kamikaze's screams act very weird, because I would leave some alive in another room/section, then I move on, and I can still hear their screams when they're idle as if they were closeby. This happened for example at the end of the 2nd level of the DLC "Legend of the Beast", right by the exit, where no Kamikazes spawn in that arena, so I thought I was mistaken, but that was an extremity of the map, so there were no enemies beyond the exit.

I also have this Mod installed, which so happens to be one of yours as well: https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=2094225020
But these two are the only sound-related Mods I have installed for the HD games.

good work man make a patch