I have been running into this problem for about a month now. Occassionaly when I am using InDesign I notice that my CC Libraries freezes. I will initially be able to use my libraries and place items, but eventually it freezes and looks as though the whole CC Libraries is a blurry jpg image (see attached photo) instead of the normal looking CC Libraries side panel. This issue seems to arrise in InDesign when I left click a placed object from my CC Libraries to edit original in Illustrator. Once I save the original file in Illustrator to update it in InDesign, and then go back to InDesign, then my CC Libraries in InDesign are frozen as I described above. The only way I have found to fix the issue is to save my work, completely exit InDesign, and then reopen the application. I am working from a 2015 Macbook Pro running MacOS Catalina, if that's helpful.