In Windows and I can see that it is happening on the first time that I access the dialog. For example:

1. you go to Security app -> Groups and open one group for edition https://nightly.magnolia-cms.com/.magnolia/admincentral#app:security:groups;/publishers:treeview:
2. Click on Groups tab -> you will see the UI issue described in the linked support ticket.
3. Move to Roles tab -> the issue is not happening
4. Come back to Groups tab, the issue is not reproducible.

As I can see it is only happening on Windows and just after opening the dialog (if you close the dialog and open it again, you will be able to reproduce the issue the first time that you access to Groups tab).

Dev note

Can be reproduced in contacts-v8 app when resizing the window.