I remember a YT years back, R123, that had refrigerant that was a greeninsh tint. Thought the tubes were coming apart, but copper numbers in oil were low. sounds like you have an issue there alright. I wonder if the humidity in the plant caused what you are seeing, if they left chilled water flowing and no drop light in the shell while open, it is definately trouble, but you are seeing something severe. Could a cleaning agent (degreaser) cause this? randy is right, eductors need to be cleaned and inspected.I'll tell you what I did one time, and I know it will sound excessive and in no way is it anything I have heard from York, but I have bench tested the eductors before. I took a brand new eductor out of the box and piped up nitrogen as the motive force, and attached a gauge to the induced vacuum area and marked what I had. at 10 pounds nitrogen, I induced a 6.5 to 7 inch vac. Had an old one that when I cleaned it, only did about 3 inches. I canned it and went with the new one. Klove put out some good tips on these issues and I would lean on what he says.
In my opinion, the refrigerant color and the oil return issues are two independent issues. I dont know what kind of labs you have in Aussie, but if possible I think you would want analysis. If you find high iron in that oil, you are pegged dead to rights internal rust. Could you even let a sample of that refrigerant sit out for a while and see what remains after it evaporates?