It probably is just coincidence but I'd check with a local REALTOR that really knows the area if you're looking to purchase. There could be some reason (leak in the lake if it's man made, some kind of adverse commercial or residential development that is going to be built in the future, etc.) I'm not familiar with Keller but I am from Texas. There, as in all lake or waterfront properties (ocean), is a season for selling. It people are looking at that area as a second home or a lot of retirees are looking to relocate because of the amenities, then they have a tendency to look when they're on vacation which is often during the summer months. This has been the case in Florida for a long time where they talk about the selling "season". People come from the north where they're facing ice and snow, see wonderful weather, blue skies and breezes and buy.
Since you're talking about "Hidden Lakes" that might be the case there as well. Anyway, contact someone who's really familiar with that particular area and try to find out if there is something else afoot before making any decisions. Good luck.
Trisha Lee REMAX Boone Realty, Columbia, MO