It's not my first early access. I do agree that we have to be patient for all the items, and story to be added. BUT this one seems like they run out of money and were rush to sale without to be even close to the proper time to do it.
I had that issue. But i noticed i am able to open the container from both sides of the rocket, so as soon as it says that the rocket is empty even i filled it on right side, i am just moving the items on left and this time it accepts it.