@robino
As Thrasher tried to point out on page 2 there are two different things going on here.
A true hybrid is where the body tube of the mod has threading that is not standard 510, but is made to interface directly with the body of a dedicated atomizer. this dedicated atomizer has no 510 connection, but is machined to interface directly with the body of the mod it matches. This gives a very clean, sleek look to the pair when all connected, as there's only 1 seam.
For most mechanicals, a screw on top cap has the standard 510 connection, which you then screw an atomizer in to. This top cap usually has some manner of positive pin that interfaces the positive post of the battery to the positive post of the atty. However, some people do not like this set up for two reasons - you get extra length and more seams between the atty and mod body, and you also have extra points in the circuit where conductivity is reliant on physical contact between two separate pieces of metal.
The SMPL is one of several "hybrid style" mods that tries to marry the two. By not having a separate top cap (or a recessed top cap) there is no longer enough length for a dedicated positive connect pin in the mod. Thus, the positive contact for the atty has to contact directly to the positive contact of the battery. This appears to eliminate both the problems people had with traditional mech mods - it achieves the sleek, simple look of a hybrid, and eliminates the extra points where physical contact is required for conductivity.
However, as amply displayed by the OP - this "solution" can cause problems of its own. VERY careful selection of the appropriate atty and VERY diligent monitoring of battery condition are both absolute requirements to use such a device safely.
I love me my stainless SMPL/marquis combo, but yeah, offering mods like the SMPL or devices like a "hybrid style adapter" for non hybrid mods for sale to the general public is destined to cause these sorts of problems.