I'm running out of ideas...
If sahilthakur's suggestion didn't work, maybe try the following (based on the recent experiences stated by Nelviticus and sahilthakur):
1) umount your microSD card
2) completely shut down the Note 2
3) remove the microSD card from the Note 2
4) do the steps needed to power on to the Android Recovery Console
5) clear the cache partition
6) reboot
Do not put the microSD card back into the Note 2. See if there are any issues with it without the microSD card.
Other idea would be to boot into safe mode and see if an app is causing the issue.
To go to safe mode:
1) completely shut down the Note 2
2) press and hold the volume up and down and power buttons
3) when the Note 2 logo shows release the power button, but keep pressing the down on the volume up and down buttons
4) release the volume up and down buttons after the boot cycle has completed and you see 'safe mode' appear on the bottom left corner of the screen
Do this without the microSD card to narrow down the issue.
If the problem is still persistent (with and without the microSD card), then I am inclined to say that there may be some defect with the phone. Could be drivers, memory sensor giving false readings, etc. Hard to say.
I really can't think of anything else to try at the moment.