While two stations chat away on 6900 kHz LSB, seems like two more operators who wanted to use the frequency have "changed" (translated) to 6900 kHz USB. That's right, flip the mode switch.
As of 1320 UTC, there are two distinct QSOs going on on 6900 kHz. One on 6900 LSB and the other on 6900 USB. Both in Spanish and both are involving a pair of stations with roughly equal signals.
See my log for the traffic on 6900 LSB that was going on while 6900 USB was busy:
https://www.hfunderground.com/board/index.php/topic,38242.0.html