Newbie with 2012 Bobcat T180 hydraulic and/or controller issue

Issue: the hydraulics on the lift cylinders "stutter", then "bounce" down to completely closed; all other operating features work fine. If mess around enough (try and use lift while this is happening) the hydraulic lock feature will activate and an error code will beep (sorry, don't have the code at the moment, just found out that the unit won't store it and you have to access it immediately...will get it later today). The longer you stay in this condition at some point you'll have no hydraulics to the lift cylinders. Occurs only when: Driving side slope (+/- 30 degrees or more); with the controls in the hand/foot option; when the left side of the unit is up-slope. If the controls are in ACS mode this does not occur. If the right side of the unit is up-slope this does not occur (in either hand/foot or ACS mode) Only happens on a decent slope. You can drive side slope for around 20-25 feet before the issue starts. All fluids and filters were just changed by the rental company before purchasing including hydraulic because it had blown a main hose. They also replaced the sensor/switch in the left joystick that switches from hand/foot to ACS mode because the ACS mode would not work. 2300 hours Thanks Barbara