Crack along a board in kitchen

Q: I have a new crack along the line of one board in the kitchen (along the seam – between boards). It’s uneven and seems to be getting worse. What would cause this?

A: Perhaps there was a spill there and water got between the boards, curling or cupping slightly the edge of at least one of the boards. Just a guess.

Follow-up Q: Thanks for getting back to me. I considered this as well. How would I go about fixing?

A: I would let it sit for a while and see if it corrects itself.