Would like some opinions on what I might have done wrong on this dining table top. It is constructed of solid walnut with bread board ends. The picture below shows a crack that has started (no doubt due to moisture changes) since the weather has started to change. It happens to be on the very edge of the table. I did my best to account for wood movement by gluing only the center tenon in the breadboard end construction. Since this is on the edge, there is no glue on this tenon and based on the location, it almost looks like it starts at the edge of the tenon underneath? Maybe I did not allow for enough side to side movement with the drawbore dowel?

Secondarily, is there anything I can/should do at this point to repair it and/or prevent it from getting worse? Note, it is finished with Arm-R-Seal.

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