Roger------------What do you have for an air compressor and what type oil is in it?????????????This has been a culpert in many cases like yours---------

You could maybe positively prove/disprove by taking your air hose regulator paint gun to that shop and see if same thing happens there----

I remember the fisheyes that appeared just after the silicone waxes came out---seems silicone is good for breast implants but not much else!!!!!!!!!!!!