No it's true, if you flip back in 8-4, you don't have Peach or Bowser, therefore when it comes to the part in 8-2/3 where you have to use Peach to fly across to the next platform, you can't because Peach isn't in your party! It happened to me last night. Luckily I didn't save when I got back to flipside, otherwise the game would have been screwed Now I have to finish the game with little to no health! ¬___¬;.

if you use the return pipe you don't have to do the puzzles again because you already did them. all the doors should be unlocked so you won't need bowser, peach, or luigi. you can skip the parts where you need other characters because the doors are unlocked. i used my return pipe in 8-3 and i was able to keep going.

two words: HA HA

i have the same exact problem, i cant get across to the platform w/o peach, i tried using luigi's super jump, but that didnt work, unfortunately.....i saved it... so how do i get past it (if some of you claim you can do it).....

quote master10000

two words: HA HA

poor you. that happened to me in chapter 4 and I had to start over. you can only repeat certain chapters once you beat a whole world. sorry!