Having owned a number of DR400’s and been responsible for the maintenance of many others I have seen this Problem repeatedly.
The temptation to just blow the leg up and send the owner always present, I had one owner come to me and ask me to just top up the legs, When I told him what the problem was and the work required to fix it he just muttered about being ripped off, got back in the aircraft and went away ( while having difficulty staying on the taxiway ).
Im sorry if it sounds like I’m castigating another LAE but the situation is clear, the aircraft is in an unsafe state, be this because of bad servicing or leakage from the legs, ether way it should not have escaped rectification at its last 50 hour inspection.