Thanks so much for the responses everyone!
I'm glad this happened because I didn't know how important it is to use two batts charged to the same level. I always use freshly charged
batteries and I have them paired off but I've never checked their volts before putting them in my VVG. I'll start checking them. If the batts aren't charged precisely the same, is it important to stack them like CATastrophe does, with the 4.1 volt batt beneath the 4.2 volt batt? I try to take all necessary precautions with safety but apparently there's still some more learning for me to do.
I did clean the spacers like Rick suggested and I reset that bay (thanks racehorse, I didn't think to do that, actually I forgot about the reset button all together) and it seems to be working. I tested the battery that I just charged in the pila in my provari and it's fully charged. So I don't know if it was one or the other or both that did the trick. I think I'm going to move my charger upstairs out of the basement where it's been for the last several months and get it out of that humid environment. I got to thinking maybe the moisture in the air down there isn't the best permanent spot for a charger.
I guess I really should
buy a meter. I may be asking questions once I find one because the meter thing has not clicked for me after watching a couple of vids. Maybe once I have one and have it my hands it will click and I'll "get it".
Thanks for the help everyone, much appreciated!