Ah! The ol' center pin issue. Only on the Pico, you can't really pull the pin back up..
Your tank has pushed the center pin of the pico down just a bit too far.
If you slowly screw your tank back on, while pressing the switch now and then, you will find a point where the ohms read, then don't read as you pass it.
It's a pita on a pico...
You need a spacer now, something about as thick as a credit card, in between the tank and the 510 connection. I took an old ATT sim card and cut a hole in in and put it on and the one pico I have this same type of fault on is fixed.
Your tank has pushed the center pin of the pico down just a bit too far.
If you slowly screw your tank back on, while pressing the switch now and then, you will find a point where the ohms read, then don't read as you pass it.
It's a pita on a pico...
You need a spacer now, something about as thick as a credit card, in between the tank and the 510 connection. I took an old ATT sim card and cut a hole in in and put it on and the one pico I have this same type of fault on is fixed.