Spoke to a girl at a 1-800 # the Can. Tire guys gave me. It is, in fact a threading and "fitting" issue, not all models are affected. The store I was in was in the Niagara Region of Ontario. The affected filters, according to her were :
17-1707
17-1717
17-1746
17-1881
17-1723
She emphasized that not all of the filters from these models are affected either. If the filter goes on properly, it's OK. That's all I can really tell you.