It's not normal,then again i'm not familiar with that machine.Google the problem and see what you get,you may find someone that has the same amchine amd can help you out.

This site here isn't very busy as you can see by the date of the posts..
Kathi

Are you interfacing the piece with the buttonhole? If not, see if that helps. Also, try using a tear-away stabilizer underneath the area with the buttonhole. If you don't have a stabilizer on hand, paper will work.

The sides of the buttonhole feed differently; one is forward and one is backward. Make sure you are only guiding the fabric but not pushing the fabric or holding it so that it feeds more slowly one direction than the other.