Anyway, we did have a Trouble like this at one point. Sucked all the oxygen out of the room. Main thing is, it wasn't so... localized, before. It affected a whole area, not just one person or one sheep.
But it could be something new. Something Mara did before she got taken into custody, but it didn't get triggered until now. Or, maybe she managed to figure out how to Trouble someone from behind bars.