By any chance do you have MaterialVariant Alpha Mode beta features enabled?
If this is the case, what you described may happen if you have the beta enabled and publish your place.
We are working to resolve this issue completely.
In the meanwhile, as a workaround, you may have to re-open and re-publish the place (make sure there’s no errors related to TexturePack in Studio Output Window). Once you re-publish, you may need to play the experience couple times to ensure the textures are fully transcoded.