I don't think you damaged the post on your batt perse. Having used the batt connector in two of my mods, the positive post on the battery is solid (good design). If something is going to give it is with the atty (good thing). Many adapters are the culprit of many things and the most common is shorts. The protection circuit on the battery is sensing this, and shutting down (4 blinks) preventing the battery from shorting out. However, if the protection circuit fails, the battery will fail.
Thanks for the link on the video. I had seen it and couldn't find it anywhere. UIt wa done in the day where he was posting to youtube and VapeTV.
Take you adapter and place it on your desk. Press the center post down so it is flush with the outer threads, it should then rest against your desk. Now the 510 side of the adapter is set. You will notice a slot on the positive post of the 801 side of the adapter, that is adjustable. Unscrew the centre post clockwise until the distance below the outter threads is about 1mm, that adjustment is now set. Place adapter on carto until it starts to feel snug, then fit to your
device, only tightening until it starts to feel snug.
If your battery operates fine with other atties and only acts up with your cartos, then chances are the adapter is the culprit. FWIW, after you are finished your KR8 cartos, but some 510 cartos, they are much much better IMHO.