[Elecraft] KX3 Frequency Shift in DATA A - What Am I Doing Wrong?

[krug261 at yahoo.com]

I don't know how long this has been going on (wow, sounds like a song lyric), but each time WSJT keys up my KX3, the transmit frequency shifts down 500hz. For example, the standard 30m FT8 freq of 10.136 000 shifts down to 10.135 500. The freq shift shows on the KX3 vfo B and the WSJT screen. It occurs on all bands, as well as if I change mode to FT4. When this occurs the KX3 screen shows: DATA; TX is pointing to the B vfo; SPLT is illuminated; and the vfo B freq is 500hz lower than vfo A. I have pressed A>B (which changes the vfo B freq back to that of the vfo A) and then held the SPLIT button (which has TX now point to vfo A and SPLT disappears). But once I key-up it reverts back to the original screen display and the lower transmit freq.
I have gone through the manual and cannot figure out what else to clear on the KX3. In WSJT: PTT Method is CAT; Mode is Data/Pkt and Split Operation is Rig. These settings have not changed.
What am I doing wrong? Or, is something wrong? Suggestions appreciated.
Bob, KA2TQV