The strips look like they have formed a tube at some point....is that the way you see it? And the tube looks to be ~1/8" in diameter????
I can't think of anything that it would be. If it's got good
oil pressure, breathers aren't pushing smoke out (I've seen some engines with bearing issues push smoke out, not from blow-by but from heat), and there wasn't flakes in the pleats of the filter, then I'd drive it for a bit and recheck it.