Web Shield blocking legitim websites and iFrames

Since the last update, Web Shield keeps blocking several websites and even embed code (audited by Thirdweb) that I have on my own website.
What can be causing this? It’s not a problem from the websites because they were all working before the last update.

With no information to work with it is almost impossible to ‘guess’ what the issue might be.

Attach a screenshot of the Avast Alert window with the Details option selected (see attached image on how, click to expand).