Hi from Canberra. I was having the same problem on my Janome. I adjusted how high my darning foot sat above my fabric, it was too high before, and my machine only like Gutterman thread
I took mine in for a service and unfortunately the sewing machine mechanic didn't quilt and so could not replicate my problem and found nothing wrong with the machine
It is now behaving for me. I hope you can get your sorted too.