Mavic (like most manufacturers) publish specifications for the maximum spoke tension. These values are widely ignored, and this in large part is why so many rims crack. Some (a few at least) will crack at lower tensions anyway, but most are overtensioned.
In the case of Mercalia's wheel I don't think it was a good choice of rim for that application. However I would also bet money that the DS spoke tension was way too high to start with. My personal view is that Mavic's tension recommendation is pretty much impossible to adhere to if you are building a 130mm 8/9/10s rear wheel with PG 14G spokes, unless you use thread lock on the spokes. Even with pretty stretchy DB spokes, and a 135mm hub the wheel will tend to slacken off on the NDS in moderate to hard use unless threadlock is used.
well I have no way of knowing what the tension on the DS is but it dont seem much different from my new Sputnik. The NDS
I was always worried about seemed slack, but then it uses plane gauge spokes all round. I dont know how long the cracks have been there but recent going over the paths on NR1 from Gravesend and round about didnt do it much good plus my weight of 17- stones. I think had it had double eyelets then this cracking wouldnt have happened as the internal wall fine; I cant see any point in single eyelets unless you are a racer? Are double eyelets a large cost difference? I was always worried at spoke breaking - I did have 2 break 1100 miles ago but nothing since. So upset at having to bin this wheel - the hub fine, the spokes fine just a crap rim & the only rim I can replace it with is another Mavic single eyelet rim with ERD 544 - no point in doing that.