Do it again, but drag the suggestion upwards until a trash icon appears. Maybe one time you used that swipe path and accidentally/deliberately clicked “didn’t” and now it thinks you sometimes want that instead.
I have to do this all the time, I’m considering nuking it’s memory
It adds the word to the input box but should also show a “correction” list on top of the keyboard.
Maybe it’s different if you use floating or split keyboard mode?