Prolonged use may cause wear of the seat mount, resulting in the gas lift giving way or raising on its own. The reason for this is that the seat mounting rests too far on the gas lift and the gas lift valve is then triggered continuously.
You can test whether the adjustment lever “still has play”, i.e. whether the lever still has a short adjustment travel without the lift tripping immediately. If the adjustment lever has “no play” anymore, replace the seat mounting with the lever.
You can read more about this in the downloadable LEITNER service booklet: