I had the same problem before I upgraded firmware to the version you mentioned.
Can you confirm you are running that version?
I noticed it took a very long time for my tablet to reach 100% the first time. Please try to charge it to full, let it drain completely and than repeat.
Yes im running that version, already confirmed.
So there is no specific time to fully charge the battery to 100%. So far i think it may be 6hours.
BTW, il try to do the total discharge and recharge again. Thanx