Description of the issue:

While holding a revolver, the player model displayed in the inventory window shows a graphical glitch (it looks to be normals related). This only seems to happen for the revolver (at least not for mining drill or vanilla bow).
Turning off "fancy item holding" still displays the issue.
While moving the item in the inventory window ("holding" it with the mouse pointer), the issue does NOT display.
The revolver has no modifications and no shader added.
This was tested on a local instance (no remote server), using Minecraft 1.12.2, the instance created with MultiMC.
Screenshots attached.

Versions & Modlist

IE version: 0.12-92
Forge version: 14.23.2820 and 14.23.2847
No other mods installed.

Java 1.8 (Oracle)
Operating system: Ubuntu 19.10
Graphics card: GeForce GTX 750 Ti
Driver: nvidia-driver-430