I’m using the desktop version of Legend on Silicon macOS on an M2 Max Laptop. A client of mine is experiencing a similar problem on a M2 Air. The flashing cursor on a Legend item that is being typed in sometimes stops being at the point where new characters are being typed in. It can end up being five to ten characters ahead of the point where characters are being inserted.
So for example the cursor is here.
If I now type in [space] h it appears here well before the cursor.
Clicking out of the Legend item into another Legend item and then clicking back into the original Legend item restores the cursor to where it should be.