I was wondering what mod was responsible for it. But when a post on the FTB Subreddit came up revealing someone else having the problem. I cross referenced their mod list to my packs own mods. Disabling everything in sequence with your mod being last. When your mod was turned off the arm model was fixed.

Hmm. Did you have any routers nearby displaying particle effects? That's the only possible explanation I can think of; nothing else in the mod makes OpenGL calls. I'll do some investigation anyway.

Nope I tested with a fresh world. After disabling the mod the problem went away.

Yep, confirmed, my fault. I'll hopefully have a fix out in the next day or two.

Ahh very good then!

Fixed in 1.0.3 release, just uploaded to Curseforge.