Well, it was bound to happen. The top on the cabinet cracked at the joint.
And this is also a really good lesson to me in my future endeavors in furniture-making. The problem with this is that the top sections are exactly aligned with the bottom sections. The bottom sections are attached to the house so they are going to be forced to move with it. The top, despite the sections being bolted together, have no choice but to move with them. Since the sections are a bit independent, the top will crack.
To fix this next time (hell, I could even re-make the top without a whole lot of problems) I would need to make the top pieces completely not overlap the bottom section joints. This would serve at least two purposes: it would further stiffen the overall structure since the top would provide additional stiffness to the cabinet, second, any flex would be need to be taken up by solid pieces of top that wouldn’t be subject to cracking.