Kerbal Space Program

I dicovered this today while playing around with an airplane at the island airfield. Buts its not specific to that location nor the craft...
What happened? I moved my plane into a hangar to make a nice creenshot. Then, in order to get it back onto the runway, i had to push it with a kerbal. After the vehicle started moving i tried to get back into the vehicle. I could climb the ladder, but it didn´t showed the "Climb out" option until the vehicle almost stopped.

Steps to reproduce:

Load the attached craft onto the runway
Enable brakes and extend ladder
Get out, climb down and up again to see the "climb out" option
Switch to the vehicle, release the brakes and give it a little push, Something like 0.5m/s should be enough
Switch back to the kerbal. The "climb out" option is gone

I think this might be related to something like this: #5391