Now that you mention it, I believe the CRJ's have a galley heater (keeps the FA's somewhat warm during boarding with the door open) that is like a small electric heater and fan. (or it is, I don't know much about it, I just know it is there).

That could be a source of something burning. Either dust or something gets in there or it overheats and the breaker doesn't trip. I remember being told that they used to have an issue with the intake of the heater getting blocked by the galley restocking form in between turns because fa's would use a clip on an adjacent cabinet and the paper would get flipped up by a breeze and block the heater intake causing it to overheat.

Either way I would guess you would have some kind of burning smell in this instance.