For over a year, my experience would be the same. Hook up a full 5lb CO2 source, soap test connections good, a week or 2 months later it would be mysteriously empty. I have probably lost 15lbs of CO2 in this manner.
Finally, last week after losing another 5lbs of CO2 I discover why. While lifting the empty CO2 out of its bracket the 1/4 swivel nut fell apart.
For me, it’s stainless steel swivel nuts from here on!!
