blocked because "unreachable"

This was already touched upon in Microsoft Authenticator issue - General - Cloudflare Community, but the thread got auto-closed recently.
We came across a number of odd issues with Planner app in MS Teams, but also with administration of Azure AD, MS Endpoint management.
As it turned out, it was caused by being blocked with category “unreachable”. I have submitted a report on, asking for the domain to be re-categorized as “API”.
Does anyone else see this issue in their environment?

Thanks so much @d.sidler - I confirm we have received the report and will make a fix to the category. This should be resolved in the next hour or so.

Looks like Microsoft has added a couple of domains which aren’t classified correctly. The latest appears to be:

According to their lists here

Thank you for sharing @learningdaily - we’ll take a look and update!