I have to disagree with you there. I see you’re running Ubuntu 16.04 LTS which is a Grade A tested release. When you upgraded to MySQL 8 you basically made your installation an untested configuration. If there’s a reason you need a newer MySQL I think it’s better to move to a newer Ubuntu release that’s tested, supported and contains the MySQL release you require. That way the community (or the devs if they can spare the time) can easily reproduce what you’re dealing with.
That being said, I wouldn’t keep my hopes up for a virtualmin release to fix this issue unless it also happens in Ubuntu 20.04 which ships with MySQL 8.