I do have connection issues with my MVP 2 and Protanks I & II. I have 2 MVP's as well as original Kanger's. They work with some and not others.
I like the MVP's around the house/office since I plug one into a USB power supply while I am using the other one. It's easier to do that than to swap out a battery. I do not like being tethered, so never use the pass-through feature. I would never plug anything into a PC USB port to charge. It's just too risky. A dedicated high out put USB power supply is only $5-10
When out and about, I do use my Itaste VV in pass through mode when driving. My PT 1's don't work on those either, but I use PT Mini's when out and about.
Rather than mess with pulling center pins on a device, it's easier to grind off a few fractions on my vaporizer. The Kangers make it easy since you pull the head from the base and don't have to worry about dust getting into the air hole. It does not take much.
Over the years, I have had numerous instances of faulty connections with various device/vaporizer combinations. It goes with the territory of vaping, so you just have to live with it.