After looking at the filters again, I'm convinced the ecore design is very flawed.
Think of the media ripping this way:
Take a piece of paper and place it on the edge of a table that has a 90 degree edge (meaning, kind of sharp). Then tear the paper along the sharp edge and notice how easy it is.
This is the same concept with the ecore. You have sharp edges throughout the ecore center plastic tube. If you had one in your hands you would notice they are exceptionally sharp. When media flattens over one of these edges it's going to be prone to ripping *easily* IMHO.
If you look at the PF53 that did *not* tear, but did indeed flatten over the center tube... this pic in particular:
You can see where the media is pressed against the plastic center tube, and you can see the center tube 'edges' that the media is trying to push through. So I have no doubt, under the right circumstances like a cold start, or high RPM, that the other PF53 filter would have ripped a hole also!!
Serious design flaw that was **NOT** well thought out, no matter how many "engineers" thought this through!