My thought would be, Have you ever used Kanthal before? Some people get a metal taste from it.
What type of wick did you make? I've only made tubes and have not had a problem with an air bubble feeding down through the tube as the liquid capillaries up even when vaped in an upright position. If you made a solid wick try opening up your fill hole, air has to get in somehow.
How thick is the liquid? What is the mesh?