Thanks for reporting this issue, Illustrator team really appreciate this.
Unfortunately we are unable to reproduce this issue in house, Kindly help Illustrator Team to nail this issue down further:
Kindly provide the exact preferences you are using and the data from below mentioned location .
Mac:- /Users//Library/Preferences/Adobe Illustrator 2X Settings
Win:-C:\Users\\AppData\Roaming\Adobe\Adobe Illustrator 2X Settings
Share the above information with us at ShareWithAI@adobe.com in a Zip file. Please mention the title of this issue as the subject of the mail.
Thanks and Regards
An error occurred while saving the commentMolly Cichy commented
July 22, 2020. Same thing happening here. I'm using CC and AI is up to date. I just got a new Macbook Pro running 10.15.6; this wasn't happening on my old computer as of last week (same OS, same up-to-date AI software), for comparison's sake. Hope they find the fix soon.