If they are splitting, maybe trim the cake. I consume cobs like you. I can't smoke a wood or meer like I can smoke a cob, and I abuse them on vacation on the beach or water. It's a nice change from the nice, easy smokes on the patio or in a smoking club.
I actually make it a point to never let my cobs build a cake, past the initial break in period of getting the bowl carbonized from top to bottom. After that first week or so of smoking I always wipe down the inside of the bowl with a folded up pipe cleaner after every smoke to prevent cake buildup; which I had read was the best way to maintain a cob since cake buildup can cause the cob to crack.
In any case, I did email Missouri Meerschaum customer service this afternoon to explain what was going on so I'll be curious to see what their thoughts on the matter are.