I just noticed today that when I went to copy & paste a line of text in a notes field (that notes field had very little text), nothing happened on CMD+V (paste).
I had been working in this small FM database for a few minutes on a machine with 16 GB RAM / 700 GB free disk space. No other apps were running at the time.
Restarting FM solved the immediate issue but also confirmed my initial problem was a FM bug.
Since I don't have a copy of the bug database, not sure if this has already been reported.