flex 6500 crashes

This is a weird one but I want to report it before I forget.
I had been primarily working 17mtr when there suddenly became an all band (perhaps all slice receiver/panadapter noise that persisted. I switched that panadapter to other bands and no noise I slide the slice down into the low 17Mhz range and still the noise persisted. I terminated the radio and restarted it. Still the noise persisted. I next terminated the slice receiver (the control with the frequency display on it. The audio stopped, as expected. I next terminated the panadapter (small x in the top right of the control). It disappeared as expected with the grey 3d-ish logo displayed. I next opened a new panadapter by selecting the bottom left icon with + in the top corner. A message box appeared with the text to the effect of the program lost contact with the radio please reconnect. There was no radio to reconnect to.

I, honestly, don't recall if the radio powered off by itself or I recycled it manually.
I was unable to reproduce.