and for your question, the closest I know of is 250.64(C)&(D) and since the Grounded Conductor is not included in either is the reason I say no.
But 250.64(C) and (D) speak to the GEC, not to a bonding jumper. And 250.53(C), which covers bonding jumpers, refers to compliance with 250.64(A), (B), and (E), explicitly excluding (C) and (D). So I don't see how 250.64(C) and (D) are relevant to where a bonding jumper may terminate.
After rereading your question I need to add that the GEC connection itself can be made directly to the Grounded Conductor but it can not be used as a jumper to other electrodes
Say we have two ground rods, that's it, and we have two places on the grounded service conductor where we may connect, the meter and the separate service disconnect. Possible arrangements are:
(1) One GEC at one location goes to one ground rod. The other ground rod is connected via a jumper to the first ground rod, or to that GEC. This certainly complies with Article 250.
(2) Two GECs, one at one location to one ground rod, one at the other location to the other ground rod. Each piece of wire satisfies the rules for a GEC, i.e. is continuous. This is OK?
(3) A GEC at one location to one ground rod, a spliced bonding jumper at the other location to the other ground rod. I gather this is what you are saying does not comply with Article 250?
I guess I'm having trouble finding text in Article 250 that would differentiate (1) from (3) and says (1) is allowed, but (3) is not. It seems like there's nothing that says exactly where a bonding jumper may terminate.
Cheers, Wayne