So I was checking marriott app on my android phone and I just removed the favourite hotel tag on one of the hotels and got the error
" We are unable to process your request at this time due to an unprocessable condition. Please try again later"
Whoever wrote the text for this error message deserves a special mention.
I am known for getting weird errors no one else gets at work all the time, my explanation is I am a very good tester who has learned from the best (my wife). When you do good testing you will get all kind of weird errors.
BTW if marriott is looking to hire me I am not available as I would lose access to the rewards program.