Thank you for your message. I am sorry you are having this problem.
Is this happening every time or did it just happen once? If happening frequently, please tell us your operating system and browser along with their version numbers.
Hey @fun_8746 1) Maybe start with a smaller selection. 2) What were you asking FF to fill in? I mean what was your prompt? 3) If you are asking FF to fill in with Text, You may consider using Adobe Express to add text.