I've found some here and there, I think it's a case of some poor quality tape. What I've found was fairly brittle, as in it can't handle the hot/cold cycles well and just disintegrates over time. I've re-wrapped some pieces here and there. I had another example of this a couple weeks ago when I was swapping out the blowoff valve, most of the tape on the wires going to the BOV and on the split loom disintegrated. I put new loom on and new tape/zip ties to hold things together better. I predominantly use only some good 3M electrical tape.
I love how I was just looking at a buddies '75 F100 and some of the factory tape is still intact. But these 1-3yr old vehicles its already falling apart. Anyone wonder if that creates more safety hazards, i.e. less protective media on wires? Let's see, a new customer service bulletin soon that tells us not to park indoors again?