I think that's perfectly acceptable, really. The presentation layer is where much of the user experience is clustered, and correct use of the displayed language is part of it. A grammar mistake is as much a bug as a misplaced button is.
I would take this as a plus actually: they were being very detailed oriented and pointing out more mistakes than would have been expected. I doubt its sustainable though, as soon as the app load increases, they'll probably become more like Apple in detail orientation (unless they are using tools, I'm not sure, I have no idea).
