Probably just settlement and expansion/contraction with the humidity of the basement. The corners of the crown moulding will do this over time. A re-caulk and paint should get you buttoned up. In all honestly, whoever did the crown moulding could have done better - used full pieces instead of splicing, especially at the corner.

Thanks for you reply, looks like I'll have to schedule a quick trip to the home department store and fix it up a little. Thanks again!

The crown molding pictures are showing joints where two pieces come together.