9-Slice Scaling pop-up automatically quits Illustrator

When I press 'yes' or 'no' to the 9-slice scaling pop-up asking "Do you want to retain the 9-slice scaling option for symbols" (while opening .eps file), Ai 2020 automatically quits. 

In a click.

Any idea why? It didn't do this in previous version! Only since last week's update.

Thanks.