I was creating a pretty long note, entering a lot of text into the "Description" field.
While the card was open, it rendered all my changes correctly. I was able to see the formatting in the expected manner, and altogether be visually satisfied that my changes were being saved to the Trello card.
When I closed the card, and reopened it a while later, all the edits made were lost. There were no accidental deletions of data from the card while exiting. In fact, exactly the data that was edited in my previous visit to the card was erased, while all edits prior to that visit were still preserved.
I don't remember how long my text was but definitely in excess of 10000 characters.
