I'm pretty sure I had leaching in my loop with X-T1 Nuke UV Green. I used Mayhems tubing 16 / 10 flexible, AquaComputer Kryographics 1080 Nickel / Plexi GPU waterblock, AquaComputer Cuplex Kryos Next Nickel / Nickel CPU waterblock, AquaComputer Aquastream XT pump / Aquainlet Res combo (there's a stainless steel tube in the res), Hardware Labs SR-1 360 radiator and Bitspower Black Sparkle fittings.
There were little bits floating around the reservoir and some bitty gunk in my GPU block. The inside of the tubing was also quite misty white rather than clear. To be honest it looked like plasticiser, even though I can't think how it got there when all my tubing is Mayhems.
I'm going to try once more with a XSPC Photon reservoir w/ Aquacomputer D5 pump, but it really looked like the tubing was the culprit, as it seemed to be perishing.