Looping Running Sound

Most of the time, when I play the game, there is an annoying running sound playing on loop. It's always the sound of a specific unit moving, usually a Spearman because of how common they are in the early game, and it's always coming from a specific tile, usually a city tile because of how commonly my units are in that area. Usually it's fixed by reloading the game, but that's annoying to do and doesn't guarantee it won't happen again. I did a google search, and it seems like others have had this problem before, but I haven't heard of a solution beyond reloading the game.