I just replaced this PSU a month ago and I lost one of the secrws that connected it with the hashboards and tried to find a titanium screw in local shops and find nothing, and I took one of the screws from a house machine and it works fine for around a month now. I upload a photo if you didn't get my point.
As long as the screw is tight enough and the connection isn't loose - there shouldn't be a problem, I highly doubt that reason alone is what killed the PSU, what is your input AC voltage?
Also just check the screw its too long as its going through and possibly touching components.