Thanks, all, for the comments here. It does appear it was a USB cable issue...traded out the USB and the problems went away! WOOT!
@Kit, good to know about the temp not being reported in SGP. That was the first thing I actually saw, but then it fixed itself, so I wrote it off as gremlins in the software :)...turns out, that was probably the first sign of impending doom.
Everything appears back to normal now regarding this issue. Thanks!