SpaceX Falcon 9 overall has an incredibly good flight record. They very early had one supplier part they didn't correctly validate.

The other failure (non-mission) was when they discovered a real unkown-unkown about COPV tanks and helium tanks in near 0-kelvin temperatures.

So yeah, they should not have made that mistake, but its also the case that nobody has a perfect record. Considering the errors most rocket companies have made, theirs seem fairly reasonable.