Pex A fitting is rotating by hand after joining

[8seconds]

I am using a Dewalt expander on Pex A 1/2 inch pipe and fittings. After joining a 90 for a sink stub out I grabbed the end of the stub out and it rotated around the fitting with some resistance. I can turn it 360 degrees. Is this normal? I waited 15 minutes and tried again and it still rotates.
I am using Uponor fittings and collars and Jones Stephens Pex A pipe.

 

[Breplum]

normal

 

[Sponsor]

 

[8seconds]

Breplum,

Thank you for the quick reply. You are very generous with your experience and knowledge and it is much appreciated.