Creating a reroute node between a class variable and a "Spawn actor for gameplay task's" class pin will cause the variable attached to the instigator pin to disconnect.
Result: The instigator pin will disconnect
Expected: Successful compile
Updated Repro Steps:
Result: Instigator connection is broken
Expected: The pin stays attached
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-90965 in the post.