Man I'm dumb...Air suspension issues

[jjmead1]

2002 BMW X5 4.4 Rear air bags only. 140,000 miles or so

I have had this car for about one year now. Three issues with the air system. Leading to low ride height in rear. So far this has cost me a set of new tires due to inner wear on rear.

Here's what I know:

Air compressor works.
Sensors are able to trigger compressor to inflate.

Here is what I think:

Air bags have slow leak.

What I don't get is if the sensors trigger the compressor, and the settings are correct why doesn't the low ride height trigger the compressor?

I have had my Indy reset the height twice and I trust them. First time I went in and had it set it rode great. After three months I had low height, went back and had it done again. It did not last as long this time. Perhaps a month. So clearly a leak right?

I am perplexed as to how to get a permanent fix. I am severely cash strapped and want to make the correct choice. Am I missing something?

All air lines seem intact and are not pinched. No sounds of a leak from inside rear of truck.

Today I removed rear wheels. I unhooked ride height sensors. I removed rear spare tire and cover from compressor. Started truck, toggled the sensors to trigger the compressor, it ran and shut off. I reconnected sensors, tires and replaced cover on compressor. Drove around. Self leveling inactive light came on and the rear height was waaaaaaay to high. Say 35 inches measured from top of rear wheel well to ground.

Headed to Indy tomorrow to see whats what. Hoping to hear from you all as well. The ride is a tad firm.