There are two we should usually expect to encounter. Ti6/4 is the grade used for forming and forging and would usually be seen by us in sheet applications. Ti3/2.5 is the grade used for machined items being of superior strength, and is the one we should expect to see in screws, turnbuckles, etc.
There's no such thing as a lower quality Ti, just the wrong grade used. I doubt that 3 Racing used inferior material, but they may have used the wrong material. I still think that the problem is poor design of the screw, or fatigue - look at the failure on the photo, that doesn't look like a good piece of design to me! HTH
