It's pretty hard to describe, but the issue is this:

Whenever I try to attack with LMB and I'm standing still, I will attack only once (regardless of the type of attack). However, if I'm moving the mouse around while attacking, everything works correctly.
I know the game thinks that LMB is pressed all the time, cause if I start shooting with an automatic weapon, stop moving the mouse around and release LMB, it just keeps on shooting till the magazine's empty.

I've tried everything I could think of: mouse filtering on and off,reinstalling, all the compatibility modes, enhanced pointer setting in windows itself, unofficial patch 9.9, remapping attack to RMB (it works properly when mapped to keyboard, but still a little jittery and not the most comfortable). I've seen someone mention mouse acceleration on the forums here, but I don't know what's he's talking about, to my knowledge this game doesn't have that.

Oh, and it's not the mouse itself, doesn't happen in other games and I've tried a different, wired one.
I'm trying to play on Surface Pro 4 i7 with the latest Windows 10 update.

So, help please : D

Edit:
Oh, and if anyone wants to suggest a walkaround, don't, I already came up with my own and it works just right, but it's kinda clunky. Right now, I'm looking for a solution.
Regardless, if anyone's facing the same problem, lemme know and I'll post it