It's gonna happen. Even with all OEM parts, it's still gonna happen. Just part of the power game. Fix it and move on.
I built a 372 a few years ago that I sold to a member. I built it from a box of parts. I ran for a few hours then came unglued. All I could figure was it had a piece of debris wedged in the air filter pleats. So, I redid it, sent it back.....a month later it broke a ring. So.....I redid it again. Three months later it came back again.
This time I just bought it back.
Luckily, the muffler had just came loose, so it was sounding odd.
I nicknamed that saw Ol Reliable.