Previously, when looking up an Entitlement from a Case, the recently viewed Entitlements would show up.
Now, even users who have view all accounts and entitlements are not having this functionality. Instead, the popup window says "The search returned more than the maximum number of rows (200). Please refine your search criteria." and shows what are seemingly random entitlements - entitlements that may have never been viewed by the user.
We recently rolled out an update that restricted account accessibility for some users, whereas previously there was a sharing rule that basically shared all accounts with everyone. I can't imagine why it would be relevant, but it was the only change made in the time period that this started.