Alfang said:
I think if you used tung oil waranty is void, squirt some thin superglue in the crack and keep going. It looks good
To me, that looks like the wood was run though a jointer to make it flat, laminated together, and... the wood decided to settle in, shift a little, and no amount of glue will hold it when that happens. The finish should not "void" the warranty. Assuming not being stored in abnormal conditions - very wet or very dry, or very hot or very cold - and assuming its less than a year old, you should be covered by Warmoth warranty. I can't speak for them though, and its their call all the way. Just my 2c worth.