If we have an anycast to targets B,C,D, this will be sent as 3 unicasts: to A, to B and to C. The original message is copied for each of the 3 target dests (only the headers are copied, not the payload). The copy is needed to prevent protocols from changing the (same) headers when the message is sent (or retransmitted).
As an optimization, we don't need to copy the first message; in the above example, we need to copy only B and C.
For anycasts to single destination, we don't need to copy anything.