Center stabilizer dropping while in storage

We have a 2018 Big Horn E3760 and store the unit with the stabilizer legs up. After a couple of months the left center stabilizer seems to have dropped down about 4 inches. The hydraulic fluid tank is full. No apparent leaks on the ground. Appreciate any comments or ideas. Thanks

internal leak in the cylinder or the valve, either of these two will allow the leg to lower.

Thanks, I was hoping it would be something simple, but I'll have it checked out. Is this something that can be fixed or have to be replaced.