It doesn't say 'defective'.

It says failed. And that can be from either wrong application or manufacture.

And the filing signed by 'weld expert' Heddle does not explain which reason is to blame.

Only you are doing that.

Heddle hasn't commented at all so he obviously hasn't said this - If he say's the welds were defective. They were defective

Let's keep it real.

Case closed.