Since a external leak would be obvious, it's possible to have a internal leak inside the jack or fluid leaking back through extension (bypass) valve(s). With the jacks retracted verify hydraulic fluid level then check the extension (bypass) valves for the CCW position. The link below is the system used on my 2018 ACE but yours may be slightly different. Skip to page 13 for more detail. The LCI website has other versions to chose from besides this basic version. I hope this helps.
https://www.lci1.com/support-motoriz...ndard-leveling
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