I think i found another issue. But i am not sure, if i do something wrong.
Take for example a model for a Fan.
Try to rotate the fan within a blueprint. Just use add relative Rotation and a value for the Speed. Connect to Event Tick (i tried both: without and with a Scale Rotator.
It’s Pretty simple, BUT: The Fan rotates like i want, but after a few seconds it stops. Is this a bug too? Or changed Epic something? In a Project with 4.15 this was working.