May 06 2021
We've encountered a bug with the Teams app and web browser where certain users will not display their contact cards when hovering over their user profile/display picture in the chat header. Note: this isn't due to the information not being present within Azure AD or AD as the contact card does display when hovering the cursor over their profile/display picture in the "Recent" Chat pane. This issue appears to only affect some contacts and not others although their information within Azure AD and AD are identical.
May 24 2021
Hello @John-Peter_Richardson Have you reported this bug on Uservoice? (or looked to see if someone else has reported it) That's the site where bugs are reported and features requested, and others can vote on them as well. Thank you.