Don't get me wrong, I'm not thrilled about loopholes you can drive a truck through (especially if the truck has MFS written on the side of it) but Congress had every opportunity to learn from their "mistakes" on EIP1 and EIP2.  Best they could come up with for EIP3 was to direct the IRS to issue regulations.  But if you think about it, anything the IRS could have come up with for regulations would have (or at least could have) directly contradicted what Congress put in the law.  Who gets priority?  Either the party who got the advance--as directed by Congress in the law--or the party who now claims the RRC--as directed by Congress in the law.  If Congress had stated (or even hinted) that the one party had priority then regs could have specified how that gets handled on the tax return.  The IRS may come up with regs at some point (let's face it, they're about 20 months behind in getting anything done) but for the most part it's too late now, returns are already getting filed with (legal) double dipping.