I'm working on an end-grain cutting board. Not sure what happened, but twice in the last two days when I've tried to glue up the long edge-grain strips, the glue joint has failed between a walnut piece and the next piece (maple or white oak). There seemed to be plenty of glue squeeze out when I clamped the pieces together, but when I started cross-cutting the first glue up to make strips for the end-grain glue up, the strip broke always at a walnut joint.
After the first failure, I started over, milling new strips for the entire cutting board, glued up the strips and again the joint failed when I started cross-cutting.
I don't think it's my milling technique - the ash, white oak and cherry strips all glued together just fine, but not the walnut.
Is there something magical about walnut that makes it harder to glue up than other woods?