It's a problem caused by buying multiple quantities of an item while lagging. It should be avoided when possible (meaning if you notice it, sell the excess before you launch). Carrying more cargo than your ship can carry will cause the server software to automatically ban you when you dock with another station.
I had a similar thing happen on Sindroms' battle server. I accidental put two thrusters on my ship during a lag episode, and as a result my ship flew at 350ms on thrusters, but drained my energy in about 5 seconds.
I don't think launching is the problem, it's when you dock that it picks it up. It can also occur while mining, you can accidentally tractor in too many goods for your ship.
Like everyone says. Lag is bad. Ive been banned on multiple accounts after clicking buy too many times and buying 5 weapons with the money for 1 weapon.
I hate my ping of 1120... when my brother is using the internet on his computer...