Let's suppose you have 4 partners and 3 elect to prepay $1,000 each. $3,000 was paid last year and allocated to those 3. That reduced the ending bank balance that is where it goes on the 1065. I believe it should also show as a distribution to those 3 partners. The 4th partner now will owe $Y on their state tax return when they file their 540. They can then take an $Y deduction on their Schedule A in the year they pay it. The 1065 has nothing to do with that. The partnership did not actually pay any tax. The partners paid the tax from partnership income. One elected not to do that, so they will pay from their income. 

Am I thinking correctly?