Janome MC 500e
Yes does happen to this machine. I learned that I will go 5 to 6 switches, then stop the machine and pull the loose end of the thread until it's firm to the fabric. Cut off the loose end.
The other times I end up with a ball of thread on the back side of the pattern is when thread has caught in the thread cutting area of the bobbin case. I take the cover off and clean out the bobbin case.
Usually I can hear if the machine is starting to form the mess on the underside of the pattern. I have also found some manufactured embroidery thread is more prone to this than others. I like the machine a lot, and have made many items from cup sleeves to kitchen towels and pillow cases. It's been a wonderful experience. People reaction to an embroidered item is fun to watch.