Hi guys, I have a KFL + for 4 months now and it's excellent! I use 28 g kanthal A1, usually on a 2.5mm dril bit, 7 wraps. I now make my coils with Kuro coiler. I used to dry burn my coils before wicking. But after seeing some concerns over the web regarding metal oxides causing health problems, I gave up dry burning. I have noticed something weird: \
-I build my coil, on ohm meter it says 1.35 ohms.
-Still with the base on the ohm meter, I wick it, put the lower part of the chimney on, prime the wick, check the resistance. Still 1.35 ohms.
-I fire the base, to see everything is fine. The resistance drops then at 1 ohm!!! And stays there!
-I put the upper part of the chimney, the tank section, fill it, vape it: the resistance is 1 ohm! Not 1.3. And stays there.
This thing never happened to me until today (that is, the lowering of the resistance after firing it). Can it be so because of the lack of dryburning in the first place?
Dry burning the coil builds up a layer of oxidation that stops the current from traveling a path you don't want (between wraps instead of through them) which is why coils usually glow unevenly until they are fired/pinched a few times, and why an evenly glowing coil is a good indication that your coil will vape properly.
Without this step it's basically a crap shoot on whether the coil will give you issues with shorting from one wrap to another, unless you space your coils to give a wide enough gap between them to ensure they aren't touching anywhere. After your coil is mounted, but before wicking, you can take a small pick or flat-heat screwdriver and gently pull the coil apart to space the coils. If done carefully you can get a super even spacing going on that should stop your erratic resistance issues. (assuming the cause is slight shorts between the wraps) With your current build you could also try raking a screwdriver or pick along the coil to hopefully re-seat the wraps in a position that won't short.
The reason the resistance only changes after firing is because an ohm meter only uses a tiny amount of current passed through the coil, which isn't enough to conduct through the minor oxidation already present on the wire, but when firing the device to take a vape the current is high enough to "break" through the poorly insulated layer and jump from one wrap to another.
If you continue vaping as-is you'll probably notice an isolated area on the coil that starts getting dark and gunking at a faster rate than the rest of the coil, which is where the short is taking place. I respect your concerns as to dry burning the coil, but even without a dry burn the coil will still darken and oxidize with use, and any shorting going on between the coils has the very real potential to be "burning" the wire and release stuff that's likely worse.
There is a possibility it's due to connection issues somewhere, although that usually makes the resistance go up, not down, so I strongly suspect it's a minor short between wraps somewhere considering you haven't been dry burning before wicking.
Have you checked for loose connections, either in your coil, your mod or other moving parts - like a center pin for example. I recently encountered a weird variation of your problem when I stuck a small piece of kanthal into the air flow control to get rid of the whistling sound. My resistance dropped from 2 ohms to 0.9. Took out the Kanthal and everything went back up to normal. Apparently there is something called " Hidden Resistance " where each time you attach something to your tank ( your chimney for example) it affects your resistance .... Don't know how it works, but that is why some veterans check their resistance several times at each step of the game - from wicking to final assembly.
I did the same thing with a piece of rolled-up mesh in one of my KFL's air holes

Although it was a bit more serious and fused the mesh against the center pin abit. The air-inlet on the KFL base goes directly to the center pin, and as the entire base is the ground anything conductive that touches the base and the center pin will cause a short.