I figured out a small bug in xlookup last week. If this sounds familiar to you, I had posted it on /r/excel when I first ran into it.
I tried reported to MS but work blocks feedback and MS doesn't want bug reports to come from elsewhere.
Basically, I was given raw data that had a space at the beginning of the header and ended in a period. When put into a table, the formula works until any F2 / entering of the cell, then it adds a space, and every time you F2 into it and Enter, you get a new space - repeat for multiple spaces.
Table header = " Table Header."