Black boxes appear over my text boxes
I have been having a problem lately where these huge black boxes appear over my text boxes. Here are a few screenshots.


They appear throughout my document, which is primarily one text box across several pages. If I move the text boxes, the black boxes move too. If I copy the text into a new document, the black boxes appear again. This is happening on two of my files.
Does anyone else have this problem? Does anyone know of any possible solutions?
I can fix it by copying my text into Google Drive and copying it from there back into InDesign. I would rather not do that, because it deletes all my formatting.
