Is this legal?
I’m not a lawyer and I don’t even play one on TV, but laws CAN be made which apply retroactively. The “retroactive” issue applies to putting a person into legal jeopardy for an act that had been legal at the time that the act was committed.
If the recount was completed, then they might have problems attempting to collect further funds, nor would that be fair, but this is not the case.
Perhaps, the better nomenclature for this would be “effective immediately”, in that the party requesting the recount would have to pay for the very next ballot counted as soon as the law was passed. This would probably hold up unless the agreement of the state officials to perform a recount was deemed “contractual”.