I have seen a lot of comments in this thread that breaks it down to, IMO, mechs are not the friendliest of New User devices. Yes there are new users that can jump right in with a mech and sub-ohm atty on top, "IF" that user does their research properly, and "IF" the peers he hangs out with "KNOW" just what they heck they are doing also. A one hour crash course discussion at a B&M just does not cut it, if that B&M were so inclined to do so. Honestly I imagine as most, the battery at issue in the OP was a re-wrap from one of the many offenders on the market, Efest, IMRen, MXJO, AWT, take your pick.
When I was working at a vape shop and had a new or newish vaper wanting to dive in head first, this was the list (updated now with newer things on the market) I told them they needed to research before I would take liability selling the devices to them...
1) Ohm's Law - read about it, get a good understanding about it, and how it works (there would be a quiz)
2) Battery Safety and Battery Chemistry - this included what types of batteries, proper charging and discharging, proper handling and care (there would be a quiz)
3) Mod Designs - does the mech have venting, if so, where is it, what are the warning signs the battery isn't venting properly (mod is hot, hissing, foul smell, etc) (there was a quiz)
4) Coil building - I guided mentorship process, I would not sell them any wire or tools until I felt they were competent enough to this on their own (this excluded ohm readers, on a mech you need an ohm reader), this mentorship I'd build the first few coils with them watching me, next couple work together, then the next couple just observing them doing it and give pointers and such. They were welcome to come in any time and ask questions and advice any time they wanted, especially during slow hours if they could, I was happy to sit and discuss things, if I got busy I'd pause the discussion, especially if a new vaper walked in
5) Choose your equipment wisely, this includes batteries, chargers, battery cases, mods, atomizers, etc. Personally IMO, if you are running a mech, especially below 1Ohm, the minimum battery you need is a Sony VTC4, best batteries are Sony VTC3 (if you can find them) and now added to the list is the LG HB6, all of them true 30amp or capable of handling 30amp loads. So with 30amp limits, lowest you will ever want to build on a mech with these batteries is a 15amp to 20amp load, giving you 15 to 10amps spare "UH OH" room in case of a mishap. Chargers, buy the best charger you can afford, light user near or above 1ohm regularly used, a 2 bay and 4 batteries, Nitecore i2 or D2, Efest LUC2, or an Xtar VC/VP/WP2 minimum, 0.6ish and below, 4bay charger and at least 8 batteries, Nitecore i4/D4, Efest LUC4, Xtar VC/VP/WP4 minimum. Have enough 2bay or 4bay battery cases to carry your batteries safely, and never in your regular pants pocket or purse pocket where keys and loose change and such can cause an issue, if need be, a cheap fanny pack is a great investment, even an old ego carrying case works real well.
I always forced the shop owners to always have Sony VTC 3 and 4's on hand in good quantity, with for mods like a SVD or such, there I would sell an MNKE or other 20amp battery for use with those, made them angry at my sales tactics for a while, but they soon learned the value of it, when one of them on my day off sold a mech, patriot clone, 4 of the first versions of the Purple Efests, 2bay trustfire charger, spool of 26awg wire, and such to a kid, and let him out the store. 2days later kid came in with an attorney, kid's hand wrapped up in a cast, mod and atty in pieces and scraps of one of the Efests, "Make it right or we are suing..." I spent six hours explaining things to everyone, replaced the mod, atty, 4 new Sony VTC4's, and an XTar WP4 all for free, just to make it right and keep the glaring attorney happy. Shop owners really wisened up after that incident.