I realize this is not the solution to this problem, but I did have a problem where when using Projectile Movement to throw a pickup, I’d spawn the pickup from the player character and the pickup would auto destroy after 45 seconds. This was the only post that’s title described my problem perfectly but was not my problem. Maybe this will help some other poor soul looking for the same solution I was.
Solution: On begin play set a delay for 5-10 seconds then get a Destroy Component from the Projectile Movement. Destroying the Projectile Movement component cancels the auto destroy of the actor.