Not sure what you mean, please try without other mods, and if it still happens then you'll need to give me reproducible steps so that I can see the bug too
Just tested with a fresh spt aki profile and just Spt-Realisum installed works fine with the standard generated config when messing with a certain setting being recoil climb under advanced recoil settings seems to break the high/low stances when it's turned off.
Steps used to Produce this below
1. created new spt-aki profile with spt-dev account for testing
2.bought gun from trader with ammo
3. headed to hideout shooting range
4. tested weapon with standard realism config worked fine
5. Setup the config to what i usually set it too, after this the stances broke when test firing while using the high ready stance
6. slowly re-enabled settings to see the culprit causing it, turns out it the recoil climb setting when set to off breaks only the high and low ready stances causing them to not display or work properly.