Additional features, settings, or issues not covered by specific Microsoft Teams categories
This is definitely a bug. I tried all the above to change my status and even deleted the text in the automatic reply box in the OWA. It still said I was out of office with the previous message in Teams. It showed me as available in the OWA. What seemed to fix it was deleting the all day event I had on my calendar-- which was not set to show me in a different location.
This is the first time this has happened to me and it's also the first time I set up the automatic reply through a mobile browser in the OWA as opposed to going through a standard browser on my laptop. Not sure if that makes a difference or helps.