Why it doesn't work

It's a genuine question. Something's wrong. I used titebond 3 for the glue up on walnut and oiled 2 full coat of Livos LINN using a white pad to make sure it get plenty of protection. It is a drip tray for a bonsai tree. At the first water of the tree, the wood expanded, bent upward and did this. I know for a fact that the Livos oil i used was made for bathroom furniture that deals with a lot of moisture. I expected somes level of expansion but not at this level. Is it because the wood's too thin and the glue join just fail.