The fix for this issue is available in the latest InDesign release 16.2.1
Please update to this latest version of InDesign to get the fix.
Adobe InDesign team
An error occurred while saving the commentAD commented
This is still not working for me. I deleted all those cache and preference documents that Ravi mentions above. It worked for a couple uploads after that reset, but now on the 3rd try it's blank again when I click "share for review" ... So frustrating.