Woodworker here. If it is a matter of water vapor absorption from different climatic conditions, no oil or finish will stop this. In scientific tests, the only thing that really slows down water vapor moving in and out of wood is a thick layer of wax, as in 1" of paraffin. Which is why they use wax on the end of boards to prevent splitting when drying and seasoning them. Of course, some finish is better than nothing, and a spit coat of shellac is more effective than most other finishes for slowing water vapor absorption. (Edit: Don't try applying shellac to your headphones though! It should be applied after smoothing and staining the wood, and before the final top coats.)
This problem with the M1060 is more likely due to making a relatively large hole in thin wood, then having it undergo some stress as it pivots.