Incompatibility with iChun's Portal Guns

[ghost]

Describe the bug
Weird rendering glitches appear when looking anywhere near a portal. The moment the portal goes out of sight, the rendering glitches disappear. No further corruption appears to happen.

Reproducibility

• I reproduced this issue with as few other mods as possible installed.

To Reproduce

1. Use any portal gun to shoot a portal anywhere in the Overworld (only dimension tested)
2. Look at either portal
3. Glitches appear (e.g. water disappears)

Screenshots/Videos

Versions
Nothirium: Nothirium-1.12.2-0.1.10-beta
RenderLib: RenderLib-1.12.2-1.1.10
Forge: 2860
Minecraft: 1.12.2
Other mods (necessary to reproduce the bug): PortalGun-1.12.2-7.1.0

Hardware
CPU: Intel Xeon X5680
RAM: 64GB
GPU: AMD RX 580
VRAM: 4GB

Log File
After initalization of singleplayer world, nothing appeared in log file, regardless of if bug happened or not. Log file omitted.

Workaround
iChun's portal mod is not open source. However, by disabling the "See through portals" option in the provided config file, the bug disappears.