Your seasoning is too thick.

Yes, that’s almost certainly the issue — either the seasoning is too thick or you’re using an oil with a low smoke point.

Cast iron doesn’t need a thick layer of seasoning. In fact, thick seasoning is the enemy. It builds up unevenly, traps burned oil residues, and smokes like a chimney because the excess oil polymerizes unevenly and then burns. The goal is a thin, hard, polymerized layer. If you can feel texture or see glossy patches, you’ve gone too far.

Same problem if you’re using flaxseed oil or extra virgin olive oil — they smoke at lower temps. Switch to grapeseed, avocado, or even Crisco. And heat your pan slowly. Even medium on a powerful burner can hit 500°F+ fast, which will smoke any seasoning that isn’t perfectly cured.

If the pan is sticky or the smoke smells acrid, strip it with oven cleaner or steel wool and start over with extremely thin oil layers. Like, wipe the oil on, then wipe it off as if you changed your mind. Then bake at 450°F for an hour. Repeat once or twice.

Thin seasoning is tough. Thick seasoning is trouble.