I have the same issue (Teams shows me "out of office" even though "out of office" is deactivated in Outlook; manual status update in Teams does not work; status change via command prompt in Teams does not work either).
Based on the threads I read the reason of having outside office meetings in the calendar might be the reason for me as well. However, it is not a solution to just delete those appointments or change the status of those appointments because sometimes colleagues
who for good reasons do not share their calendar with me share individual out of office appointments with me so I know they are not available. Changing those appointments would have to be done by them and result in incorrect status for them. Deleting such
appointments from my calendar would result in me missing relevant information.
I suggest Teams should only reflect the user's own OOO status as set in Outlook.
you can manually edit the "OOO" status from others' meetings on your own calendar. But I definitely agree with everything you said! The various bugs I have encountered are infuriating.