Yeah, it's normal on this phone. I see it raise in charge while idle a lot, esp after any amount of constant usage. I'm guessing it's harder for the phone to estimate the charge while it's drawing a lot of power during usage, so when it goes idle, it is able to more accurately estimate the charge level, which results in it raising the percentage a little. I've seen mine go up as much as 5% or so after sitting idle. Usually right after I get done playing a game or doing something that's very resource intensive.

 

I've heard of it also, haven't seen it on my phone yet. If it persists, just try a simple reboot or if it's persistent, go into clockwork > advanced menu and wipe battery stats once you get fully charged and see if that shapes it up.

If you still have it after that, throw it against a wall. I mean try a different rom/kernel combo.

Although after closer reading, B31 w/ lean is a pretty good combo that many have used so hopefully one of the earlier ideas work. It may just work itself out after a few days also. Battery reporting can be odd for the first several days on a new rom.