Bush trips used to save the time that you ended. A couple sim updates ago, that broke. If you start a leg and continue, you will advance along time as normal. But if you end the bush trip, and come back to it later, the starting time will be the starting time of the original leg.
So in other words, if leg 1 starts at 6:05am, you get to leg 2 at 6:26 and continue. You then get to leg 3 at 7:02. You then exit. When you come back, you should start leg 4 at 7:02, but instead you start at the beginning of the runway and it will be 6:05am.
There are some bush trips that this can be annoying. The Iceland trip, they start you early in the morning so you can experience the sun breaking over the mountains, which is visually stunning. But saving the bush trip and starting legs in a later session, the surroundings are too dark yet to sight see. The bug has been logged, and hopefully it will be fixed at some point.