Each roll of the dice is a separate wager or set of wagers, as in the case of Placing 6 & 8. Nobody is making you keep either or both of those Place bets on the table from roll to roll. The Place bets are not contract wagers even though they are not "one-roll" bets.
It's the same formula and logic that you would use for making one, two, three, four, five, or six Place bets...or a Place bet with the Field bet...or a Place bet with a Lay bet...so on and so on.
So go back to your question:
You invest $12 and you declare it over and ready for a computation when
(frequently) 1/2 of your money invested remains at risk ?
And take into account that all of your money on the table is "at risk" for any roll of the dice. It doesn't matter whether a 6 or 8 came up on the previous roll and you collected or not. Why is the situation, as you say, "not resolved"?
Place bets either win, lose, or push on each and every roll of the dice. Sounds like a resolution to me. Look at your following options for each of the 11 number outcomes in the game of craps:
2, 3, 4, 5, 9, 10, 11, 12 - PUSH. Your choice to keep the Place 6 & 8 up, or take down one or both.
6 - WIN PLACE 6 BET: PAYS $7 for each $6 wagered. Your choice to keep the Place 6 & 8 up, or take down one or both.
7 - LOSE PLACE 6 & 8 BETS. Your choice to make another bet or not.
8 - WIN PLACE 8 BET: PAYS $7 for each $6 wagered. Your choice to keep the Place 6 & 8 up, or take down one or both.
One can see that for any number but the 7 rolled, it is up to the player to keep the bet(s) up or take down for the next roll. When the 7 is rolled, the choice is to make the bet(s) again or not. A choice must be made for each roll, even though most players keep the Place bet(s) active for each roll of the dice except the come-out roll, even though that is an option.
The bottom line for wagers in the game of craps that are not contract bets (i.e. Pass Line and Come bets that have traveled to a point number) is that each roll of the dice is akin to a new bet.
good luck
BTW - I have seen my rationale "disproven" if you will, but I still stand by it for better or worse.