Why would left front strut rod pull out of upper strut mount.

What is your question?

A friend had 4 new tires installed by a tire shop and afterward noticed vehicle pulling to the side, and front end noise. Upon inspection, the strut rod and nut had pulled out of the upper mount hole (most likely when it was on the lift)and was way off center under the mount "hat". The big nut was still on the strut rod, so we jacked up the vehicle, positioned the rod back into the mount hole, and lowered the vehicle. The struts had been replaced a couple years ago with aftermarket ones. Should the threaded rod, and nut actually be attached to the upper strut mount somehow, or does it just set in the hole with room to move? Thanks for any assistance.