I think that depends on the service?
what? how does one define "taint"? the whole point is that taint is an arbitrary Chainanal and CEX definition we have no control over. its a byproduct of a transparent ledger. therefore two UTXOS with different histories are nonfungible by definition. 1 btc != 1 btc
In my definition a tainted coin is a coin is one that’s been moved after minting