This must be the same thing I heard down here in Houston early this morning (11/25). Someone dominating 1670 on top of usual WMGE with soft 70's-80's oldies (If You Leave Me Now, Lady in Red, Wicked Game, Sad Eyes, etc). Listened from ~0420-0510 CST, no announcements of any kind, sounded like a Spotify playback with short gaps between songs. IRCA Mexican Log shows a CP for Reynosa, so maybe a possibility. Just checked the RGV SDR and it's there, coincidentally with exactly the same songs I heard earlier.