Any instances of a Blueprint class that were given a custom label in the World Outliner will have their labels reset to the object instance name whenever that Blueprint class is recompiled.
The label only resets in the World Outliner's tree view; other places such as Actor Details will continue to show the custom actor label text.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-122020 in the post.
|Component||UE - Editor - Framework|
|Affects Versions||5.0-early access, 5.0|
|Created||Aug 19, 2021|
|Resolved||Aug 24, 2021|
|Updated||Nov 30, 2021|