Love this mod, but I have a weird issue that perhaps is caused by a bug so I'll report it, just in case.
I'm running SPT 3.7.1 and Hitmarker 2.5.4 (with default settings), as well as a number of other mods. SAIN, swagnuts, but nothing that I would think interferes with Hitmarker.
I had an encounter with a scav, where I could visually see and hear (from Hitmarker) 6 separate hits. There was only a damage popup for a single one of those hits though. I was honestly surprised to see the scav eat 6 rounds without dying as well, so I'm wondering if the visual + sound hits that didn't spawn an actual hitmarker graphic, were actually not really hits?
I was hitting the scav with .300 blackout AP + .300 blackout CBJ (easily pens up to and including class 5) and he appears to be wearing the BNTI Zhuk-3 armor (class 3), so every hit should have ripped right through. I'm not running any ammo or armor-mods like Realism or anything like that.
Either way, the mismatch between hit-sounds and hitmarkers is what I think might be the bug, that doesn't seem normal.
Here's a video of the encounter