Is a loose tooth with crown on it normal while doing orthodontics?

I have had orthodontic buttons put on my back three molars on all sides in order to fix an open bite in the back that was caused by Invisalign and clenching 10 years ago. My ortho is having me do box elastics to extrude the upper molars down to close the bite. I have a crown (1 years old) on one of these teeth which feels pretty loose, especially while eating. A couple others are "loose" but not as loose as the crown tooth. Is this normal? Should it eventually settle?