I just thought I'd add that this issue occurs on my unit also.
It isn't something that I'm bothered by or worried about, but the fact remains that it does occur. I don't remember if this happened on 1.01, but the fact that I can't remember it happening suggests that it probably didn't (since I do look at my OLED from time to time... frequently irritated by the screensaver - but that is another issue altogether).
I don't have any information as to what events occur prior to causing this, or what actually causes it, so nothing useful there. I can say that within a couple of refreshes of the OLED, the reporting returns to normal.
I haven't noticed any other statistics displaying variable code or randomly blank data. At this stage I would suggest that it is isolated to the temperature information.