Seems to be a bug with channel conditions. UAblAbilityComponent::InternalCancelAbility gets called, but since the ability IsProcessingUpdate() it gets deferred into the m_PendingCancels. Problem is, the // Check for Channeling… block in ablAbilityComponent.cpp goes ahead and sets m_ActiveAbilityInstance to null, so in HandlePendingCancels it’s null and isn’t able to appropriately finish the ability.
I’m guessing that // Check for Channeling… block should not be nulling the active ability instance?
Edit: Ok this was only a problem because we had a local modification that set m_IsProcessingUpdate at the top of the tick.