I would like to add, my older MacBook Pro, the messages display correctly. So, something YOU modified, you didn't think about all the potential "other" issues you created that were UNNECESSARY to create in the first place. If I may offer, think like an end state user before you launch an update to ensure you didn't create a new problem.

I'm in Hotmail everyday at home and work on Windows, Linux, and Mac (from 2012) with no issues. see screenshots Can you show the issue and block what you don't want seen.

Did you try Firefox in Troubleshoot Mode? https://support.mozilla.org/en-US/kb/diagnose-firefox-issues-using-troubleshoot-mode#search104

Try to clear all items for a single site. https://support.mozilla.org/en-US/kb/remove-websites-address-bar-suggestions

Did you clear your browser cache? https://support.mozilla.org/en-US/kb/clear-cookies-and-site-data-firefox

Not sure what Gremlin corrected the problem, or, maybe, numerous issues were reported and behind the scene, problem was resolved because what was problem is no longer a problem.

Glad to hear, mark it as resolved and have a nice day.

So, something YOU modified, you didn't think about all the potential "other" issues you created that were UNNECESSARY to create in the first place. If I may offer, think like an end state user before you launch an update to ensure you didn't create a new problem.

This is a Support Forum as it is not some form of direct chat or ticket system with people at Mozilla.