Might have been a slight uptick in the propagation. There is music on 11780 most nights, that's Amazonia, from Brazil -- a station located near the capital that serves the Amazon region, Rondonia, Mato Grosso, and similar regions.
Without having any specific frequencies mentioned (or locations of the FB posters you refer to), that's the only obvious station I can think of that plays music on the 11 MHz broadcast band.