Absolutely they changed materials and manufacturing process on the new ones. I have a set of the old and new. Old were made in China and say what you will about China, but both the component materials used and manufacturing processes on the Chinese ones were definitely better. BTW, China also happens to be the worlds leading producers of aluminum by a large margin. (I work for an aluminum casting company and all we do is aluminum casting all day every day)
After purchasing Hawk, GSM probably saw an "opportunity to optimize" manufacturing. Or in other words, finding cheaper materials and manufacturing plants so they can make larger margins on each unit sold. There are many factors or things that could have changed... metal composition, porosity, quenching, heat treating, etc.. If I had to take a shot in the dark, I would be suspect of the heat treating on these first. I would use a rockwell hardness testing gauge to measure against the spec. Regardless of which detailed step of the process caused this problem, quality control in general is probably the number one thing that suffers when moving production to a new facility, especially a cheaper one. Not totally surprising to me this could happen.
This is a major safety issue and should be GSM/Hawk's highest priority to investigate. I'm very interested to see how this turns out. IMHO, they should be asking for the stick to be mailed back to them for testing like the rockwell hardness test I mentioned before along with other tests.
If they do not ask for the stick to be mailed back to them for testing... that will be a screaming red flag for me that they do not give a crap about the quality of their product or safety of their customers.