In Reply to: Just had a look at Jetstar posted by TnT on Thursday, 19. July 2012 at 12:54 Bali Time:
This is exactly what would have happened...
When you choose the flight there you get JULY, AUGUST, SEPTEMBER pop up from left to right, but then when you choose your return flight SEPTEMBER, OCTOBER, NOVEMBER pop up left to right. You've most likely assumed the right hand month was still September. Easy mistake to make, seems much harder to admit it though :)