Red flags if multiple neighboring homes go on the market at once?

[David Garcia]

3 homes on the same block, 2 of which are neighboring have gone on the market in my farm area within 2 weeks of each other.  They are priced moderately based on comparable.  I personally find this a bit suspicious but still plan to get eyes on them this weekend.  What could be something to induce this aside from just chance?  Anything in particular I should pay a bit extra attention to?  Anyone had similar experiences to this?  Thanks.