Thank you for your patience all this while. The fix of the issue is now part of InDesign’s latest update, Id 13.1
Update your InDesign through Creative Cloud app to Id 13.1
For Mac users deleting this file was the solution for me:
Macintosh HD/Users/<USER>/Library/Caches/Adobe InDesign/<Version #>/<Language>/InDesign SavedData (only this file "InDesign SavedData" has to be deleted).