Everyone,

I am using an FT-1000MP with wsjt-x (multiple versions) with a SignaLink USB audio interface.  

You can find my Radio Setup Screen and Audio Setup Screen  and a video of the behavior described below on transmit here:
https://photos.app.goo.gl/wpahFAtUDy6p6gAf7

I have successfully utlized wsjt-x for FT-8 with the FT-1000MP almost from the initial introduction of that mode.   Years now.   
I correctly set up my FT-1000MP based on the SignaLink instructions for USER mode here:
http://www.tigertronics.com/ft1000mp.htm

I am using the USER mode which activates PKT + LSB on the front panel but with the above instructions I end up on USB.   This has worked for all digital modes for years.  

I correctly setup SignaLink USB  for Windows 7 based on instructions here:
http://www.tigertronics.com/windows7_8_10_SLUSB.htm

This setup worked beautifully until a two days ago when suddenly, I noticed that, upon transmit from wsjt-x the frequency was shifting down by -0.5 MHz with many, but, not all transmissions initiated from wsjt-x.

After two transmissions, the contact lost my signal due to frequency shift (that was my first heads up).

The frequency shift does not occur outside of wsjt-x transmit.  

Now, two days later, I have migrated to the latest version of wsjt-x (previously was using 
2.3.1 from May, 2021 now using 2.5, gone through all my menu settings and checked and rechecked setup settings in wsjt-x to no avail.  

Oddly, when I first noticed the the shift it was negative.  Today it is positive.  Always it is 0.5 MHz in step size.

I have carefully gone through the FT-1000MP menu system for hours and all looks OK to me.

The shift does NOT occur outside of wsjt-x when I transmit outside of User Mode.

If anyone has any thoughts, I would be interested to hear them.   I am, now, two days on, at a loss.

--
Mike - KM2B