HI
@Morriganpoe and welcome to the forum. The most common cause for leaking out the air holes is a coil head not being properly installed/tight. There is a small clear delicate oring that makes contact when the you screw the coil head into the bottom of the tank. When you take it apart to clean, check this surface area of the bottom part of the tank to make certain it is free of a burr or any other obstruction which could effect the seal. You want the coil head screwed firmly but not over tight as it can also mess up the oring. It's a big issue when the tank leaks in this manner but it's usually easily fixed.
The other time I have had a leak out the air holes has been when the coil is gunked up or burnt. The only thing you can do then is put in a hew coil.
Good luck in your journey.