The few Smok devices of second generation that I have, the G-Priv2, G150, Q-box, V-Fin, bought from the finest (and somewhat dearest) dealers, never had any problem to this day.
Their previous devices, up to the R80, were built to a different standard of higher quality, and not truly comparable to their later offerings.
Smok build devices to the numbers. There are way too many subpar devices that shouldn't be on the shelves, and are not weeded out at the factory. Sometime entire batches have had problems.
When you couple bad QC with a refusal in providing proper warranty, it is easy to have scores of customers which, feeling powerless with a new and defective devices in their hands, start lamenting - and rightly - against Smok.
I had my bad luck with leaking mesh coils. Three packs (15 coils) straight in the bin. Vape coils have no warranty of sort (except when is open/shorted) - which is wrong; and it is something the vape dealers haven't fixed, nor have any intention to fix.
If a coil visibly leak or make dry hits, it is not functional - and should be replaced as per current warranty laws, but I haven't been able to achieve anything.
So I buy coils which have no known issue, but it is something that will have to change at some point, they can't apply Chinese warranty rules to western markets.
This is Smok. Big, cheap, most times reasonably built, but managed from some Flintstones characters. I avoid Smok if there are alternatives.