It does seem like Mercedes system is a tad more prone to these kind of things than the ones which have the mechanism in the middle of the wing instead of in the endplates.
And this kind of failure was off course exactly what people were wondering about when DRS was introduced, questioning the safety of it over the F-Duct. Glad they found out in time and nothing serious happened on track, but I am pretty sure both Mercedes and the FIA will have to look into the problem closely.