OK - not good, or maybe good, depending on your view. Hi. 

I cannot totally reproduce the problem.  However, I can reproduce the problem with the Fake It but the problem most likely is not WSJT-X.   When using Fake It the VFO should shift to emulate operating SPLIT.  I now see my TS-590S VFO does not shift when using Fake It.   This produces the erroneous shift.  Strangely, Fake It works fine on the other SO2R radio which is also a TS590, however it is a SG model.   The data connection to this radio is direct via the USB virtual COM port.  The 590S is communicating via OMNIRig.  Dunno -  this could be the difference in Fake It VFO operation.  My personal fix is to just use SPLIT.
  
Having said all this, I cannot reproduce the WSJT-X SPLIT problem.   so....  SPLIT works fine now.   During the contest turmoil perhaps I did not have the 590S in split for the WSJT-X split mode?  Totally possible.  Who knows.  I am a senior.......   The one fact that makes me think I am still sane is that my friend had the same problem.  He does not use TS590's.

73 Bill N4iQ