I did a few tests, and it seems that :
-Changing a bunch of my settings doesn't affect the bug.
-Moving one tile to the left doesn't affect the bug (but moving anywhere else does, by making the sound not play).
-Destroying some walls/doors¹ (specifically, walls/doors that destroying makes it easier for the 'secret door sound' to travel to me) "fixes" the bug.
¹See attached screenshot
-This isn't specific to secret doors? I'm pretty sure i heard a regular door's sound play too loudly as well, though i didn't record it, and failed to reproduce it.
Basically, it seems that this bug only occurs on my end, at a probably very specific distance from the sound. (Also, with two doors between me and the sound, like in the first swarmer one.)
Since the sound also isn't supposed to play at all in the save, maybe the cause of the bug is something like "division by zero", which can differ by OS and CPU, during the sound's "pathfinding"?
In which case, it would be pretty difficult for you to reproduce the bug (for starters, i'm still on Linux), so yeah, probably not worth investigating further.