Yes, I used peppermint oil for a long time, maybe 9 months or longer. Eventually I got tired of the taste, as you do.
It never affected my atties or my lungs, and I have super-sensitive lungs that can't take more than about 5 cigarettes a day. It seems to me that the actual quantity of oil inhaled during
vaping would be microscopically small, maybe about the same as occurs with aromatherapy oils, and to the best of my knowledge no one ever said that was a bad thing.
But like everything, it's the quantity, the dose, that is the critical factor. Inhale several ml of any oil daily and it might have some sort of unwanted effect. For vaping, as an added flavor, we're only talking about 0.2ml per day, maybe less. Peppermint is very strong, so hardly any is needed - 1 drop per 20 of base liquid is generally enough, and too much in some mixes.