Editing the bCanEverAffectNavigation flag on an Actor Blueprint is propagating the value of the property to the Blueprint instance, but fails to properly update the navmesh according to the new value. This is a regression from 4.20.3 (CL-4369336).
This was reported and tested in 4.21 (CL-4541578). This was reproduced in Main 4.22 (CL-4614594)
Results: Phantom obstacles in the navmesh are left behind after disabling 'bCanEverAffectNavigation`
Expected: The navmesh should update properly when the bCanEverAffectNavigation flag is turned off
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-67028 in the post.