I just got my first defective 510 atty. It was a Joye510 not a Janty if that matters.
It crackled like crazy. Not a normal crackle at all. More like a sharp sparking noise, only there was no lit up area or vapor.
the atty actually leaked fluid on the battery side. I couldn't drip it at all. No vapor and the liquid would run right through to the battery end.
Inside the atty = it looked normal. On the battery end, one of the 2 vent holes was plugged with some white material. Something must have dislodged in manufacture and got stuck there. I thought about trying to poke whatever was in there out, but because it was a minutes old atty, I decided to send it back.
Weird thing is I could vape it fine with a full cart. That was enough to slowly moisten the atty bridge. It would still leak on the battery end, but slower.
Didn't want to take a chance on it screwing up my passthrough so I immediately removed it.