Thanks again!
I am pretty sure I found the problem.
It turns out that the poly middle section of my KFL+ has rough edges on both ends and really doesn't seem to sit fully flush and completely right with the two SS sections. I was also filling it to the rim and had too much wicking material.
I reverted back to the steel middle section, shortened the wick legs and only filled with about 3.5ml of juice.
Only used it like this for 30 min, but so far not a drop. I think the poly section is a bit wonky and compromising the vacuum. The o-rings look good on that section and everywhere else, so that is all i can think of.
I will keep my eye on it, but I bet it was the poly section coupled with overfilling.
these should work ... or shoot me a PM and I'll send you a couple.
$1.87 Replacement Tank Section for Kayfun 3.1 / Kayfun Lite (3 Pieces) 3-pack - ships with one of each color at FastTech - Worldwide Free Shipping