With CTM installed, Immersive Engineering has blocks that flicker, namely blocks that are designed to support CTM (like the engineering blocks). Images:

It's hard to show in pictures, but it's very irritating when looking around. Wasn't sure where to post this, but since this only occurs with IE blocks that specifically support CTM I'll post it here for now.

CTM: 0.3.1.16
Forge: 14.23.4.2732
MC: 1.12.2

Latest version of CTM seems to have resolved this issue, but I'll keep an eye on it. Closing.