Theres factors when it comes to getting covered with cpo or extended warranty for sagging air suspension as most dealers won't cover if sagging is caused by a tear on the bag but will cover if the air compressor itself or other related components are faulty. If they agree to cover a damaged bag after factory warranty has expired its out of good will this is something Ive asked specifically with BMWNA before I purchased my platinum extended coverage and Im guessing it would apply for CPO as well. A bottle of wine during your visit may come along way
EDIT: found this from
StatenEye 's thread
WHAT IS NOT COVERED
The BMW Certified Pre-Owned Protection Plan and the BMW Certified Elite Protection Plan provide specific
coverage against defects in materials and workmanship. There are various items that are not covered by these
warranties for enrolled vehicles retailed on or after January 1, 2014.
Suspension
Ball joints; bushings; center tie rod; coil springs – sagging (except for leveling system pneumatic/hydraulic springs);
control arms and brackets; idler and pitman arms; stabilizer bar links and supports; strut elements/shock absorbers
(dampers); tie rod ends and adjusting sleeves; trailing arms, thrust struts; wishbones.
Good news is he got covered but doesn't mention the actual cause