Have you tried restarting InDesign? Also, what's your setup, version, OS etc? I have a weird instance where all my text vanishes when i edit it but when i double click on the frame it shows again, I think it's an M1 issue as it doesn't do this on my iMac. Try restarting your InDesign.
Dave Clayton - Loving #AdobeLife Trainer / Instructor Author - How Do I Do That In InDesign