Nothing runs when phone is hard off, not the OS not batterygraph.

My guess is that either

a) Batterygraph has no data so it draws the last known value for the off period (likely)

b) You didn't off it.

To exclude b) just power it off, count to 20 and hold the power button for a little while. You should see the white LED fading in. DO NOT LET IT FINISH. This is just to make sure it's off, because after it appears off it still does stuff for a few seconds and pulling battery can corrupt root.

Once you know it's off, pull the battery. See how that shows after a while.

Note, however, that the phone is NOT off if it has power via USB, be it charging or connected to a PC or whatever. It boots to a minimal stage, where daemons like BME start but no user login (IIRC). If it is charging and "off" then the CPU might as well be at 50% for what I know but it's likely that in that stage data about load is not available.

Also, IIRC the Catorize bug was fixed? It had to do with the fact that the menu always scrolled in the original. Once Catorize or any folder thing kicked in and there was no scrolling, the code that did the elastic band thing never finished, bouncing one pixel forever and eating CPU.

That can be fixed by either using ApMeFo to make folders (but no to few) or not scrolling (which is hard) or killing the Hildon thing. I do distinctly remember them fixing that in 1.3 - I no longer have the bug. I use ApMeFo for 10 folders or so with zero issues.

Anyhow, back to the point. There is no CPU when phone is off. Also, please use either batterygraph or the commandline to see voltage of battery when charged completely. (x-term command is "lshal | grep battery").

You might have a feeble battery, as suggested. Oh, and, get cpumem-applet. It offers insight on CPU load all the time. Once it seems to not go down, use top or conky to see the troublemaker.

Also, how many images, videos, sounds do you have? A bad/lot of media can have the tracker track for hours.