AC system holds static pressure but not vacuum

[focusgg]

2005 Ford Focus 2.0L with FS-10 compressor.

January 2016 I replaced the compressor due to bearing noise. Also replaced condenser, accumulator, orifice valve, and associated orings. The system passed a vacuum test. Since then the compressor started to groan, but still put out cold air. The refrigerant had a slow leak over six months. I injected up dye and thought I found a leak in the condenser, so I replaced that and since then the system won't hold vacuum. However, it would still hold refrigerant for a couple months up until last week. Now it leaks out over the course of a day.

The system won't hold a vacuum for more than a minute, but it will hold static nitrogen pressure at 100 psi all night. There's UV dye in the system now but I don't see any leaks.

I think the first step is to replace the compressor, but I'm honestly not hopeful that this is the solution. Thoughts. How else would you test this system. I don't have a sniffer, but I could buy one.