It Only Gets Worse - part the first

Yes, it only gets worse. As speculated earlier, it's even more likely that Spirit/Boeing went to the gray market for titanium to save a penny-a-pound on titanium. For the record, it's among the most expensive metals in manufacturing.

Titanium is generally 20-40x more expensive than steel per unit weight.

What about aluminum? While aluminum is widely used in skins, less so in internal structure.

The cost of raw titanium can be up to ten times higher than aluminum, making it a significant consideration in manufacturing.

And aluminum is about 80% of an aircraft. Is it worth it to cheat on the other 20%, of which titanium is some unknown (so far) proportion?

The McDonnell Effect rises its ugly head. Some thoughts from that NYT report:

The titanium in question has been used in a variety of aircraft parts, according to Spirit officials. For the 787 Dreamliner, that includes the passenger entry door, cargo doors and a component that connects the engines to the plane's airframe. For the 737 Max and the A220, the affected parts include a heat shield that protects a component, which connects a jet's engine to the frame, from extreme heat.
...
So far, Spirit's testing has confirmed that the titanium is the appropriate grade for airplane manufacturers. But the company has been unable to confirm that the titanium was treated through the approved airplane manufacturing process. The material passed some of the materials testing performed on it but failed others.
[my emphasis]

So, it appears that in addition to all the other issues, we now know that Boeing's Plastic Plane can vomit an engine, or two. Oh joy.

You need to read the whole story to see the trail, so far known, of the titanium in question. On the face of it, sure looks like gray market trading to save a penny-a-pound. The Spirit of Satan.