This is a bit of a speedy bump, but I think it's warranted. I've found the answer - or so I hope.
It was caused by, for some reason, too many levelled lists.
I've been working on a large-scale rebalance project that involves using a whole lot of tiered levelled lists to improve weapon and armor variety. That meant that I had to make a giant chuck-ton of interwoven levelled lists to get the kind of granularity I wanted. This problem must have started somewhere in the middle of that, as, based on process of elimination (meaning deleting everything until it started working right), the cause was just plain having too many list records.
I deleted most of my lists and, lo and behold, it worked. Fire rates stopped going nuts. Weapons started sounding as they were meant to.
I've started the process of porting my lists into a plugin separate from my main file. That seems to have worked out just fine. It's going to be a major pain to port my stuff without breaking references, but it's something that's been a long time coming.
I'm going to keep testing this to see if it all worked. If I can be sure, I'll update the OP with a pointer to this post. I pray for anyone else that nobody ever runs into this bug like I did.
Edit:
Disregard above. It's back. I've completely deleted all of my levelled lists. It came back just today. My only option is to get rid of the plugin entirely and start over from scratch.
I have to throw out half a year's worth of work just because of this bug. I still don't understand why this is happening.
Edited by PAPVAFS11, 11 January 2020 - 07:51 AM.