After ungrouping, an actor “GroupActor” stays in Outliner and cannot be removed.
Repro:
Group two actors together with Ctrl +G
Ungroup them with Ctrl+Shift+G
Look at the outliner
Thank you for the report, the team is looking into this.
once you have grouped the items, a new right-click menu option becomes available to ungroup them, if you use the menu option instead of ctrl+shift+G to ungroup them then everything works as expected