I have noticed this behavior in a number of builds now, up to and incl. 85.
After some time (30 minutes to an hour, say?) of using NodeXL, chart refresh stops working. I've usually noticed this when I've minimized the chart, then try to bring it back. The chart frame renders, but the canvas remains "transparent",
that is, it contains a static image of the spreadsheet behind it.
Closing and re-opening the worksheet doesn't help.
Closing and restarting Excel on this worksheet seems to reset something, and charting works again.
I don't know how to repro this; but I've seen it often enough now that I'm relatively sure that I'm not imagining it. Please let me know if there are any logging or debugging steps you'd like me to take.
thanks for a wonderful tool