I'm having a small visual glitch bug. Have a look, https://www.4shared.com/s/fzq49Yx7vca .

Mod list - https://paste.ee/p/iZy2m

Any thoughts on what could be causing this issue?

I can also confirm this issue, along with other entities, namely chests, occasionally becoming transparent when the storage is in the field of view, even if clipped. Not a priority issue in my opinion, just an annoying one. I keep my storage cells far, far underground to avoid my chests suddenly becoming holograms lol.
Having worked with minecrafts tesselator and transparency layering, I know it can be a royal PITA to deal with, and the only advice I could give is change the order in which things are drawn, and be certain to pop any matrix changes when finished. God I do not miss dealing with the tesselator...

Environment:
Java: 8
Minecraft: 1.12.2
Mod pack: FTB Revelations
Manual changes: Removed fluxnetworks-1.12.2-3.0.1.jar; Added fluxnetworks-1.12.2-3.0.2.jar
Config: Default

Edit: Pics or it didn't happen.

Fixed in dev.