Oh great... Charging problems are back, this time only affecting one of my 6a's (its actually my dads). They are totally worse this time. The phone won't charge with any length of cable, USB port is ON, but zero response even after rebooting. My dads not the kind of guy to take his phone to a repair shop, so I'm trying to rule out whatever I can. As an overview, it seems like charging problems started with the update to QPR1, I fixed them, then they came back (on one phone so far) with QPR2. We tried more contact cleaner. And scraping it out with a toothpick. My phone is charging fine still. I'm going to connect it to a computer and see if it starts charging. I'll also connect it to my phone to see what happens.
Sorry for all this trouble. This is super frustrating for us to figure out, and I can't test his phone by going back to stock Android, because its his only phone and he must have it working at all times for work stuff.