Front Air Strut question

[britcon]

2005 4.8

Have had an issue with left front corner drooping overnight. Doesn't happen every night, and varies - sometimes a little low / sometimes right down. I figured it was the Air Strut leaking, and ready to replace. Today I go out and entire front end ( left & right ) is down. Rear is OK. Start the beast and both sides pump up OK. So, my question - why would right side go down ? is there a common airline or valve that would bleed right when left leaks ? Compressor works fine. Rear bags are OK, so " accumulator " must hold air OK ?
Thanks for any suggestions you may offer.