A arm to frame supports

Shasi, the lower rear a-arm hanger as you've seen, is only a stud welded onto a u-shaped channel. I've seen about everything on the car break, and your hanger is not the first. It looks like an enterprising former owner repaired one (of four) with a chunk of steel. No problem as long as the repair is sound. Usually, someone lathes down the stud weld to gain back a tiny bit of camber adjustment, and the stud promptly breaks off.