upgraded 6 sites today - have no issues like that

@senolsengul do you use a content builder or template framework?

@senolsengul Could you check in "Extensions - Manage - Database" if there are database problems shown? If so: Which? And could you check e.g. with phpMyAdmin the value of column converted or table #__utf8_conversion(replace #__by your table prefix) and report back the result? And of course alsdo answer @HLeithner 's question about page builder or template framework. Thanks in advance.

The issue is related to the theme used. We have resolved the issue for now.
Problem is resolved when Turn off Javascripts Compress in theme settings

Thanks

@senolsengul Just to be safe and sure you don't have problems anymore: Could you check in "Extensions - Manage - Database" if there are database problems shown, and report back the result?

Thanks @richard67

Database checked and no problem

@senolsengul So would you say the issue is solved or it is not a Joomla core issue? If so, please close this issue here or ping me here then I can close it for you.

Meanwhile it turned out in the support forum that it is indeed an issue of the Helix Template's js compression. According to following post in the Joomla Support Forum they are working on a fix: https://forum.joomla.org/viewtopic.php?t=980412&p=3606170#p3606339

Closing as not a Joomla core issue.