Not at good idea and not the best way to solve the problem, with the component being a land grid array you may still get shorts. I would suspect there are no solder dams between the pins of the footprint on the PCB and also you paste deposit could do with fine tuning.
The footprint pads should be approx. 0.6mm this allows for 0.1mm clearance round the pads and a solder dam of 0.2mm, used these in the past with no problems.
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How can the unconnected pins not be unconnected if there are no pads on the PCB?