Thumb imagery for page doesn't match opened Blocs Page

I’ve hit a problem - the thumbs for my Blocs pages are how I remember them. However, when I open these pages it seems like a Bloc has disappeared. I noticed my ‘join the e-list’ call to actions are missing when I open quite a few pages although they show in the page thumb. See the photos page example attached. I’ve gone back to earlier Time machine versions of the site the seem issue is apparent there now… Is there a fix for this issue? Does it sound like anything you’ve seen before?