I have no trouble admitting that I have pinched a tube or two over the years.
And that user error is by far the most common cause of tubes failing right after installation.
But I have ALSO encountered tubes with production errors.
I had a batch of Geax tubes that would rupture during, or immediately following inflation.
A close examination showed that they had a thin streak runnin the length of the tube.
When inflated, this part of the circumference would do ”all” the stretching and stretch to failure.
A previous member here theorized that rim/tire combos making a kind of keyhole shape could also create the conditions for localized stretching and thereby thinning the rubber to failure.