My chair suddenly started lurching precariously from side to side, and when I took a closer look I noticed this inner ring around the cylinder that keeps the chair centered had popped out and vomited a bunch of grease everywhere.
I can push this thing back in and it'll sort of click into place but a few minutes of sitting later the chair starts wobbling again.
It's an unrepairable replaceable part, you need to get a new gas cylinder that fits or a new chair
Or buy it again new, then stick the busted cylinder in the box and say it came like that and get a refund