@HughJanus that's very strange, I've tried multiple fresh installs of the mod from the Nexus upload to beta versions on here and that one keeps coming up for me (I spend a lot of time in Valentine fist fighting so I noticed it every time I'd play), the only other mod I have that could be considered gameplay altering is 'Rampage Trainer' but I have no idea if that could be causing the bug. I'll keep my eye out and see if anything similar crops up in other areas of the game, hopefully nobody else runs into it, but if they do, increasing the FallTimeDeath has definitely fixed it for me. I've been playing with that altered setting and the bug hasn't come up since.
Also just out of curiosity as I haven't spotted anything in the config about it, is it possible to change the force/distance applied to a ped when you throw/dismiss them after grappling? Just a little something I was thinking of playing around with if it can be done.
To add on from lexo's comment, I've been having the issue with NPC's dying after really short falls for some time. When they hit the ground, first they lay there for a moment, then they stagger and grunt, then they lay there for another moment, then they die. A great place to test this is Valentine, lots of small elevated ledges like the saloon's entrance, if you grapple an NPC and throw them off you'll see it happen quite a lot. At first I chocked it up to being an issue with my custom ini configuration but it's still happening after a fresh install to the latest version of the mod.
However, I found a brute force fix. It was FallTime that was causing it I believe, for some reason the millisecond timer keeps going a little bit after they've hit the floor (I think, but i'm guestimating), not sure if this is a thing with the mod or the game itself, but I was able to give that issue a fix by doubling the default values below. Now NPC's don't die when they fall like 2 feet. I'm sure there are more precise values that can be put in-place of that though.
Done a little quick testing with the latest version, I'll post more feedback the more I play. It's feeling really good so far, noticing that combat reactions feel a lot more believable than the version I was playing with (the one on Nexus), and the mod seems to be interfering much less with missions now, as previously I was having to toggle Ped off when playing them as it seemed to bug out hard; this is no longer the case! One quick note though, I noticed in the new ini file that player invincibility is toggled on by default so I had to correct that manually.
Thanks for your work on the mod!