Packaging or Restarting the Editor sets the “Player position” to “SelfActor” (Left side of the image). It’s saved and compiled as “Player Position: PlayerPosition” (Right side of the image).
I tried to create a similar scenario but I couldn’t get my Task to change from Player Position: PlayerPosition to Player Position: SelfActor after restarting the editor or packaging out the project in 4.18. I did repro this in 4.18.2 so if you could, if you haven’t already, try seeing if the issue is fixed in that version. If its not do you mind sending me a repro project with that in it so I can take a closer look?