Mercedes M Klasse Hybrid suspension issue

A faulty bellows valve could indeed be the source of the suspension issue you describe. Have you attempted any diagnostics to confirm the air leak or inspected the valve itself?

Thanks for the reply I haven't done any serious diagnostics myself I'm not that technically skilled How would I go about confirming the air leak in the bellows valve What exactly should I be looking for and is it something I can realistically check myself

Given your description and lack of technical expertise, it is advisable to take your vehicle to a qualified workshop for inspection. The symptoms point to a defective suspension air bag valve. Replacing this should resolve the issue.

Thanks a lot for confirming my suspicions. I took it to a workshop, and you were spot on! It was indeed the bellows valve. Repair cost me around 590€. Now the suspension is working perfectly again.