Carrier noted in the 2255-2400 UTC time period. The op did some tests, switching the carrier on and off, which were observed here, so we've confirmed it really was RCW. No audio, but perhaps next time...
I suspect it might have been RCW because Lupo was coming in so well (peaks to SIO 333), and others were reporting lots of pescadores from Latin America on 43 meters, so we had some sort of an opening.
I have observed mystery carriers around 6925.11 before, and now suspect they may have been RCW, or at least some of them. There are likely other pirate stations that we do not know about either from outside NAm, or even here in NAm but from areas where there are not a lot of listeners, and the people involved may not be "connected" with the mainstream pirate radio hobby community. I've occasionally trawled around on random online SDRs in the midwest, and sometimes observed weak signals on 6925 and elsewhere that are obviously pirates, and were not propagating here, nor reported by anyone else. I might try to make an effort to search for them more often. I strongly suspect there's more fun stations to listen to on 43m (and elsewhere) than we think there are