Crash on AIPerception inheritance

This has been bothering me for several hours and I am still having issues getting a reliable reproduction of the bug to occur, so here I go.

  1. Create new Blueprint project(does not matter works on c++ too) - I went with Top Down
  2. Create child blueprint of the TopDownCharacter(Content->TopDownBP->Blueprints->TopDownCharacter)
  3. Add AIPerception to the Child Blueprint, Compile and Save
  4. Add AIPerception to the Parent Blueprint, Compile, Save
  5. Remove the AIPerception from the Child Blueprint , Compile, Save
  6. Remove AIPerception from the Parent blueprint, Compile, Save
  7. Add AIPerception to the Child Blueprint
  8. Enjoy the crash

This sounds strange when explained as a test case, but the usecase for this would be reimplementing something in the parent class but forgetting to remove it from the child class and cleaning up after.

It also happened to me on a live project where I have Save after compilation, the editor did not crash, but refused to reopen after the editor was closed, also the project failed to compile using the RunUAT

Crash Log

Hi aknarts,

Thank you for the report. I was able to reproduce this behavior so I’ve created JIRA UE-49783. Our developers will be investigating further. Follow that link to monitor the status.