I have installed a few of these, and never had a problem other than not getting the DIP switch's set right, <<< PIA
The OSP power supply's, are 150 ma and would have no problem with the 20ma-40ma required by three units,
PIR (infrared) is the lowest at 20ma
multi tech is the highest at 40ma
they are very simple to wire, the power supply has a hot, neutral, two blue wires (20amp dry contact) for light switching.
for 120 or 277v just connect one of the blue wire to the hot, and the other will go to the load.
do not mix the HV blue with the LV blue as they are very different in size.
on the LV side it has a red (24+) Black (24-/common) blue (motion detect return) Gray (photo cell/motion return)
each sensor just wires in parallel, red to red, black to black, blue to blue (with the exception of using the gray for the photo cell operation in which you would cap the blue for that unit and connect the gray to the blue from the power supply.
there are three other small wires on the OSP power supply, that are a dry contact SPDT for very low current HVAC applications, which you would not use for the lighting control:
Common green
N/C Brown
N/O Brown/white
Do not connect these if your not using it for HVAC use
Other then a miss setting, I'm not sure why one is keeping the lights on if the units are wired as above.
Try to hook up one at a time to see which unit is the offending unit, then check the wiring and DIP switch's