As strong as that spring was holding everything tight up against the end plate, I rather doubt oil would, or could, get by. In theory you could be correct, I don't completely discount your observation, but I doubt it's an issue here at least. I doubt Wix's engineering staff would have done it without some consideration of the consequences.
Not to mention, if that were the case my previous UOA's would have given some indication (3,1,7,7,0,0 ppm Al,Cr,Fe,Cu,Pb, Sn and 0.3 insoluables don't indicate a filtration problem after 5500 miles). I will have the current UOA back next week and will post it. If you'd care to look, I believe most of the previous UOAs are posted here in the UOA secton. The last three have been with Wix filters, though I only posted two, I believe.
Can't speak much to the observation of the filter element. It has obviously done the job for me. The filter specs I listed earlier are what they are.