There is a new third-party rendering engine, called SKIA, in 12.30. So, things might look different. You can revert to the old engine following these instructions, and check if that fixes the issue.
But I also suggest logging a case with Qlik Support (if entitled to direct support) or your responsible partner (if you have one), because at some point the old engine will be dismissed and we need to sort out possible bugs. Thanks!
Daniele - Senior Technical Support Engineer at Qlik If a post helps to resolve your issue, please accept it as a Solution.