In the latest version, i don't get the blue, red, pink and so on to say if a block is placed wrong or not and i cannot turn it on or find the setting that does so. might be just me?
image of the issue: https://imgur.com/a/OQsotWQ

I probably missing something but... Can't you temporarily override all of OpenGL pipeline with low lvl calls like glBindProgramPipeline, for while litematica world is drawn, so that only vanilla shaders are applied?

Shaders have always broken all such colored overlays (including the vanilla chunk border renderer). I have no idea how to fix it or if it's even possible to fix it. So the only solution I can offer is to turn off shaders while you need to see the overlays.

@SunSerega I tried that, and it kind of works at least for some shaders. But with some shader packs it's still broken and also introduces rather irritating flickering z-fighting issues, perhaps because of some shader blurring?