Most rods are either forged or molded (pressed) in powdered metal and sintered. I don't know what V10 rods are; probably PM. The 'broken' rod is made in one piece, machined at both ends, and then broken at the large end. Bolts are inserted and then the rod is assembled to the piston and pin. This process has been used for decades in 2-stroke engines, especially in outboards. It's a proven process and is used in HP V6 outboard motors running 8-10K rpm. Like Gmsux says, it's to keep the cap from walking. It's also a cost saving idea in that only 1 part needs to be manufactured instead of 2.

Rods usually bend for 1 of 2 reasons: They get pulled apart and contact something like the block, or simply bend due to compression from hydraulic lock. Since yours didn't break apart and was still running, the only logical explanation is hydraulic lock. It's either water, fuel, or oil.

How did the knocking start? Did it start knocking immediately after starting it one morning?