Daystate / Coltri MCH-3 failure question

I’ve had this unit for a couple of trouble free years and just recently I noticed some compressor oil coming through the air drain.
The sound was also very slightly off within the last operating hour.

If anything was different I was filling a large tank from empty and doing it in stages. The run time under load was more like 20min instead of my usual 10min top up. Cylinder did not get too hot to touch.

So I tore it down and so far the only abnormal finding is shreds of plastic (or very hardened elastomer) in the primary cylinder head. (Shown on the towel above the head)

IMG_1593.jpeg


Any idea what this could be? Debating whether to pull pistons and dig into the block.

Thanks, David