The mystery -550Hz carrier within 1240AM. I'm not the only one hearing this.

Here in WV, I'll do the late night drive home from work, and sometime MW DX'ing, if nothing is on C2C AM. But, if C2C AM is somewhat interesting, I'll tune-in to local 1kw 1240AM WVTS, and even drive right by the TX site. Well, for the last week, when I get more than a few miles away from that station's site, I hear a HET tone that is somewhere from 500Hz - 600Hz in there. At 1st, I thought this to be yet another DSL internet carrier radiating out, but I hear this all over while on the drive, except very near the WVTS TX site. I even see this carrier on the 'lil SDR display of my newer Xiegu G90. I've even heard this in the daytime, so I thought it to be local. However, Boomer, near Pittsburgh, is even seeing and hearing, this on his Kiwi SDR, and told me that the carrier is -550Hz from 1240kHz center. I've just asked a recently moved to FL friend if he hears and sees this. So, now I suspect that this isn't local from WV, unless someone is running several watts of power, and it can skip. Question is, can a 1240AM station be that far off FREQ? Maybe, someone grabbed an emergency back-up transmitter to get back on-air after all these Mid-West tornadoes? This timing would be about right. So, anyone else seeing and hearing this?