Help with air strut
 

I have a 4.8is with air ride on all 4 corners. Recently BMW replaced both front struts and I noticed that the compressor has been kicking on every time the car starts. So I raised the air ride and jacked the front end up. I sprayed everything wit soapy water and found the culprit. Where the air line feeds into the strut there is a bronze nut. The leak is coming from around where the nut seats into the plastic housing. My question is, since my struts are less than 2 years old, and still under warranty, do I just need to tighten that nut or does the piece need to be replaced?

It's a tight reach but get in there and tighten it up first.

You can try tightening it but before you do I suggest you get a sense of how tight is tight enough but putting a wrench on one of the other ones and feel how much pressure it takes to move it. If you have a torque wrench that would be the best way to measure how tight it needs to be. You can also try some silicone on the threads.

In your case I suggest taking it back to the dealer as there is a 2 year warranty on parts.

I would just take it in if it is still under warranty. Tightening that nut might strip the fitting and the shop will say that YOU yes YOU must have broke it and it is not cover under unauthorized maintenance by owner.

As per TIS (and maybe whoever worked from the dealership on your car maybe didn't observe the procedure), the nut has to be unscrewed gently, and the connection has to be examined for damage & dirt. When reassembling, it has to be thoroughly cleaned. The O-ring has to be replaced if damaged. Tightening torque is 4 Nm.

So, if it was over torqued, not cleaned, or the O-ring was bad, there is no seal.
4 Nm is ridiculously low. I have a small torque wrench, and when I tightened the same connection at the rear, at first I thought the wrench isn't good, it's that low.......