Your material is changing for the solid bodies based on the configuration (As Welded vs. As Machined). It looks like a material was applied at the body level after 1/2 Clearance Hole7:
It's not there before 1/2 Clearance Hole7:
In the As Welded configuration, the overall material changes to A572 Gr 50:
and no material is applied to the individual bodies:
Strange behavior. But, the fact that there are 'As Welded' and 'As Machined' configurations indicates that this used to be a weldment, but the Weldment feature has been deleted. Add the Weldment feature back in and then delete the body specific material. After that you can delete the Weldment feature (and probably the As Welded config) and the model will then behave correctly.
Interesting, that took care of it. Not sure why the designer started as a weldment and then deleted it. Rookies...
Thanks for your help!