Nodes do not continue to push txs that have already been propagated throughout the network.
They all pass it on until the whole node network is aware of that specific tx.
Nodes are not obliged to push txs that have already been propagated throughout the network.
But some of them have a patches which push non-confirmed transactions over and over again.
This behaviour is not invalid or misbehaviour.
What would be a legitimate reason to push non-confirmed transactions over and over?
Isn't re-boradcasting it over and over and keeping it in the mempool just adding to the
problem as to why it wasn't confirm the first time?
It is understandable if your tx is good and after a few days you repush it when a bottle
neck is over, but nodes pushing for weeks or months seems like misbehavior.