Twice I have bought a new weapon, then put a color on it, then when I go check it doesn't have the color. It sticked at the second time I bought the color, but that's just wasted gold (was using black, mind you >.<). Dunno if it's lag, but I'm pretty sure that's not supposed to happen, right?

Make sure when you paint a weapon you don't click another item till you see the money come out of your savings.

I painted my mech the other day and found (because of the recent lag) I was painting a part then clicking another quickly and it would paint that one instead of the original, as the money was taken.