Either all the valves are leaking by in order for all jacks & slides to move, not likely.
Could be low on fluid?
With all jacks up & all slides in check the reservoir, the fluid should be within 1/4-1/2" below the opening. If not top off with 15w motorcycle fork oil. The fork oil will help with the popping/creaking when the jacks are deployed. Once reservoir is filled operate the jacks & slides a few times to mix fluid & work out the air.
The system could just have air in it? Operating the jacks & slides several times should work the air out.
Check the fluid minimum a couple times a year.
Danny & Linda
Full-timed 10+ years
Former '13 FB owner
Traded '13 GMC Denali DRW D/A
Currently rv & truckless