This bug occurs when more than one level references the sublevel.
Occurs in 4.18P4 CL 3676890
Unable to reproduce in 4.17.
This is a regression.
Result: Editor will "freeze" in Updating Asset References
Editor is unable to be closed normally, but does not appear as "Not Responding" in Task Manager
Expected: Selected actor will be deleted or renamed
Head over to the existing Questions & Answers thread and let us know what's up.