The speed with which a significant fraction of devices failed when put in the field does raise questions about their testing and what actually drives their schedules. Obviously we've no inside knowledge, but the first two thoughts that come to mind are that the testing was inadequate and that the schedule was driven by management or marketing priorities rather than the readiness of the product.
I think the first is unarguable: whatever tests Samsung did were clearly inadequate. Whether this is because they just didn't do any real world testing (just used it in the lab in controlled conditions), or because there was a difference between test samples and mass-produced models (they wouldn't be the first to have made that mistake) we cannot know, but there's no avoiding the fact that a significant fraction failed quickly. There had to be something badly wrong with their testing to miss that.
The second is harder to know, but is a common factor in these stories and Samsung have form with being a hierarchical, top-down, command-driven organisation, so I'd not be surprised if that had been a factor in poor decision making.
In any event yes, this is an embarrassment rather than a disaster. This is a showcase device, not a mass-market product that was intended to provide a significant chunk of the year's sales, and the failure isn't endangering anyone. So it's not as significant as the Note 7 failure.