The first two engine started to go through the qualification procedure, and upon tear down there were observations of some anomalies in the hardware that were considered potentially dangerous – certainly not desirable,” noted the ASAP.

Hmm. Does anyone know, how many Merlins have flown relative to the engines used on Ariane V and Atlas/Delta? I would have thought by now that Merlins would be one of the most flown engines in existence, with an incredible track record. Remember that time they relit the first landed booster over and over and over again - after it had fallen out of space? These things are incredibly tough! It just seems surprising to me given how reliable they are.