A user sending coins broadcast transaction hash to bitcoin network. Now if someone is able to copy the message (hashed transaction) and relay it multiple times it could lead to possible disruption.
Eg:
Node 1 sends a transaction to node 2. Node 2 forwards to node 3 and so on. This transaction gets mined.
Now what will happen if node 2 will try to relay the same message again?
How this is prevented in bitcoin network?