Hi Corvus ,I had the same problem ,with the same machine .only difference mine was intermittent.
I could run it all day without problem ,next day I had to rethread after 5 tacks,next day good again .
I looked at my threading ,I changed needles ,even room temp ( it seemed to happen when it was cold in the workshop )
I changed the company who supplied my thread and I haven’t had any more trouble .