When OptiFine is installed along with Forge and the Create mod, moving the mechanical belt causes the belt’s texture to glitch out constantly, without OptiFine, this doesn’t happen.

Hi, thanks for reporting- could you post a GIF of what you're seeing?

https://imgur.com/a/rqVftsd

This issue has been addressed in 0.2.2b. Thanks for the report and feel free to re-open if need be.