We are on Sitecore 8.2 and just upgraded to update 7 from update 2 and we are now experiencing issues with field validation. When a user goes to approve or publish an item after making changes they get "You cannot approve an item with validation errors." But the field(s) in question do have valid data. And furthermore, if you go to the review tab and click on the validation button, everything comes back green (all fields with validation are fine).
We have no custom validators on the items that are having issues. And if an admin goes in and changes the workflow state to approved and publishes it works as expected.