As a part-time maker, I can say that morta is in fact harder to work with generally (splinters) and has a reputation for burning out more easily. That said, I haven’t had one returned yet. It’s not surefire, but chances go way down if the maker is very attentive to sanding the bowl. And I would never send one out without a bowl coating for insurance. I’ve only had one burnout on a pipe that I couldn’t sell for other reasons. No coating. Ended up a shop pipe so I didn’t take all the precautions I should have.
Morta really does make for some nice pipes — and if well made shouldn’t give you troubles. Good the maker is replacing. I mean, in the end, we’re putting fire in wood. Sometimes the wood just wants to ignite.