[0.21] disappearing text using footnote

When I hit footnote all the text in the editor disappears/ becomes invisible. As soon as I start typing the footnote, the text in the editor reappears. So the text hasn’t been deleted, but it’s invisible.
Compiling the footnotes works well now.

I created a new project from scratch and it didn’t happen.
The other project was a text I copied and pasted from Word.