Clips are pixelated when using adjustment layer and look

[Zucchera]

I CAN'T figure out why my images are pixelated. This happens when I add an adjustment layer and select a look.

The pixelation happens anytime I move the slider on the look.

[Peru Bob]

Try resetting the preferences:
https://community.adobe.com/t5/Premiere-Pro/FAQ-How-to-reset-trash-preferences-in-Premiere-Pro/td-p/...

If that doesn't work, try resetting the Workspaces:
Reset a workspace
Reset the current workspace to return to its original, saved layout of panels.
1. Do one of the following:
• Click the Workspace menu icon and select Reset to Saved Layout.
• Choose Window > Workspace > Reset to Saved Layout.
from here:
https://helpx.adobe.com/premiere-pro/using/workspaces.html

If that doesn’t work, try updating or rolling back your graphics driver directly from the video card manufacturer’s site.