If a parent blueprint is compiled and then play in editor is utilized. The child blueprint will lose categories in it's my detail's pane until recompiled.
Note: Licensee reports that variables reset to default values if the child blueprint is not recompiled and afterwards the map is reloaded. This was not reproduced internally, however it is included here for the sake of brevity if it is caused by the same error. To reproduce, follow the same steps here. At Step 11. Do not recompile, instead, go to:
File>open Level>FirstPersonBP>Maps>First Person Example.umap and press Open. The variables inside of the child blueprint should reset to a default value, even if alterations were made.
1. Download and unzip attached project
2. Open Editor (BlueprintTest.uproject)
3. Open Parent_Child Blueprint
4. Open Parent Blueprint
5. In Parent blueprint, press compile
Warning appears: "One or more blueprints have been modified without being recompiled, do you want to recompile them now? PROTO_BP_Blueprint_0"
7. Press yes
8. Press stop
9. Switch to Parent_Child blueprint
10. View Details Pane:
Category: Test is gone, variables are still there.
11. Press Compile
Category: Test reappears.
Categories disappear from child blueprint My Details pane until recompiled.
Child blueprint does not lose any categories or receive any errors after parent is compiled.
There's no existing public thread on this issue, so head over toAnswerHub just mention UE-19401 in the post.