With Rubidium 0.5.2a installed, parts of textures on mekanism and Immersive Engineering blocks are glitched as shown. This does not affect all models, seems to happen primarily with those that have connecting textures (Alloy Kiln multiblock, mekanism's cables, pipes.

Issue still exists with version 0.5.3.

I experienced this glitch today with the Ultimate tier of cables, but strangely not the others. Seems to be a bit inconsistent.

Fixed in 65d3dda