Trying to pinpoint a very slow ac refrigerant leak

[Christopoli]

Hello, I'm trying to pinpoint a very very slow ac refrigerant leak (charge lasts approximately 1 month). I'm not entirely sure where it's coming from, I've checked with a uv flashlight, but couldn't see any dye near any point that'd make sense. I've replaced the compressor and some o rings by where it connects to the condenser, just wondering what the cause is likely to be..?

2014 CX-5