Bobcat 864 looses auxilary pressure

Hi all. This is my first post and unfortunately had to turn to the forum for some advise. So here's the issue ; I have hydraulic nursery tree forks and when I attempt to apply pressure to pick up the root ball the forks seem to loose pressure. If I continue to hold the micro switch I can keep a tight grip, as soon as I release the micro switch then the forks slowly start to loose pressure and open.
Any advise would be greatly appreciated
No apparent leaks
No codes
Full with fluid

Bobcat 864 looses auxilary pressure