Had a few leaking at the suction line shut-off valve and one that had a bad weld at the compressor where the suction line comes in. Also, almost all of the Lennox R-410 units we've installed had light oil residue at the high and low pressure switch fittings.
Nordyne got word from their service valve vendor that leaky 410 valves were out there. We had to change one. Same unit had a leaking low pressure switch. Have had quite a few leaky LP switches on Armstrong pumps.