The levelers use needle valves to control the fluid when the jacks are operating. When the jacks are down and under pressure, the needle valves are seated/closed. If they start getting dirt in them, the dirt can prevent the needle vales from holding fluid and the jacks can pop and drop every so often.
I had Ramco jacks on my Monaco and like a lot of jacks there was a poor design for venting which usually splashed out fluid over time. Which means some dirt might be getting in. I had the issue with my front jack dropping a 1/4" every few hours when I had the front end really lifted. I took a turkey baster and removed as much fluid as I could and then added it new. It helped the situation.
With that said, some of these change intervals can be a little quick. If you decide to do it, you could probably wait another year or two.
Don & Mary
2019 Newmar Dutch Star 4018 - All Electric
2019 Ford Raptor Crew Cab