“poisonous” transactions and you include them in your next transactions
Why Splitting Your BCH Coins IS a Good Idea in the Long Term
Jad Wahab

There’s not such a thing, if you send me DSV coin and then I mix it with a clean UTXO, I obtain an UTXO only valid on ABC. But my original UTXO is still valid on the SV chain. Because SV node will reject the mixed transaction. That’s FUD.