I think this problem was discussed elsewhere, but I think the Steampunk early models had this issue with the 510 pin but in later models it was remedied. Neither of my steampunks allow leakage into the battery. I should know, I used them experimentally on all my new RTA builds, and some of them just DUMPED whatever amount of juice right onto the mod the first time around. I did get leakage down through my silicone SLEEVE however, so it turned my copper mod green (did come off with some rubbing ETOH) so now I use one of my beater mods to test my new builds.
I really think the Steampunk cannot be beat in a lot of ways, when it comes to price point for value, especially if you are not averse to a heavy mod. It's smooth, great battery life, and decent TC. My copper Steampunk door is a bit dodgy (why I have the sleeve, that and drops) but my gun metal silver one doesn't, so much. I'm not sure if it's due to the metal in manufacture, or what. I think the door is my main complaint, but I've found a remedy and honestly I like the sleeve for drops.
I guess knowing what to look out for (and returning a mod without a good 510 pin for replacement) might make it easier to purchase this mod, as it's not entirely certain what model you will get, and etc., but if you get a "good" one, I don't think you will be disappointed. To the OP (who may be gone by now), perhaps a warranty might be in the cards if it's still under warranty. Sorry to hear about your experience.
Anna