Well I would have answered this differently 2 months ago but here we go I currently have a 2024 Defender max limited and it is a very nice machine and my boss ask me 2 weeks ago which one he should get, I told him to go test drive them and he ended up with the Ridge ranch edition I really like...
It sounds like the vent is either plugged or if it has a check valve in line in the vent line it maybe stuck unplug your vent line and see if it still does if it does then check the nipple where that vent line was hooked up and make sure it's clear