There are two reason:
1, Since the system has taught the coordinates(X, Y) of the component pick-up positon set on the "Pick" data screen, the distance between components whose pick-up coordinates are specified exceeds the range within which the system can pick up components at the same time.

< Range within which the system can pick up components at the same time>

Nozzle Number	Range
501	0.075 mm
500, 502, 503	0.15 mm
504	0.25 mm
505, 506	0.4 mm
507, 508	1.0 mm

Example: For the No.508 nozzles, they cannot pick up components at the same time if the distance between the MNLA L1 Head and the L2 head exceeds 17 mm +-0.15 mm.

Corrective action:
Teach the coordinates (X, Y) of the component pickup position set on the "Pick" data screen again so that the distance between components whose pick-up positions are specified can be within the range within which the system can pick up two or more components at the same time.

2, The system checks if a component is released. Since the system automatically corrects coordinates of the component pick-up position during PWB production in this case, at some point of production the distance between components may exceed the range within which system can pick up components at the same time.

Corrective action:
Uncheck the radio button "Release check" on the " Add info" tab invoked from the "Component" data screen.