Same problem, Bought this middle of last year, When i first assembled it the gas lift was about an inch from the floor but at the time i still thought this wasn't quite right but hey i just went with it and used it.
Over time the gas lift has sank even further into the base and is now scraping the floor (marking my flooring).
But unfortunately i can't find the receipt so now i'm furious.
The quality of this chairs gas lift and base is just mind boggling stupid, Who ever designed this with theses tolerances needs flogging. Why on earth would you have a gas lift chair and sit it this low in the base.
Luckily i kept my old chair and it just so happens the base plate is the same so binned the corsair junk and used my old one.
Seems like this is a common problem, Just a shame corsair aren't coming out and admitting it.