Thank you for your support. The issue is now fixed in the latest update of InDesign.
Please upgrade to the new InDesign 14.0 from your Creative Cloud Application.
If you are unable to see the update yet, click on the menu (three dots) on the top right corner of Creative cloud app and click on “Check for App Updates”.
Let us know your feedback in the comment section.
InDesign TeamAnonymous commented
I'm having the same issue. Is there a solution to this? My Overlay Panel do not expand and it's getting frustrating. I tried to close and re-open InDesign but still the same issue. I have a project I need to finish ASAP and this is getting in the way!!!!!