Problems with all pages since Millau upgrade

Since upgrading our sandbox to Millau I am receiving numerous errors for all pages that didn’t exist pre-upgrade.

Some have been fairly easy to resolve, but there have been well over 100. It’s very frustrating that so much work needs to be done to fix all of the issues that didn’t exist pre upgrade.Why are they errors now, but not before the upgrade?

Some of the errors I don’t understand how to fix, one of them is in the screenshot, any ideas?

As per Chandra’s response to me yesterday. This is part of the release notes. Makes sense when you think about. I do wish there was some way of displaying these type of messages differently as I consider them more of a warning vs an actual error.

As of Millau 11.1.3, we now report inaccessible fields as Page Problems to aid Page Builders in resolving inconsistencies between the Page Composer and the runtime. Users with Skuid Admin or Skuid Page Builder permissions may now see Page Problems. This does not represent any change in behavior for standard Skuid users.