Q//?
I am thinking it's a valve sticking,(That's Correct) causing the pressure not to divert properly. Does someone have more info? If it is a valve, where is it located (in the union connection? (Yes It is)

A//
Bad Lowering Control Valve (Inside Lift Cyl second stages) and Lowering control valve (OUTSIDE located at free lift Cyl, a built-in mast fittings. in the union connection) could be any of this 3 valves. my best guess... take a look to a valve located at free lift cyl in the union connection using a Double Pointed Scriber to cleand-up or cause to change the actual condition.