Understanding Mosfet Gate current
IIRC, this is related to SPICE, in general: the elements have numbered pins. Where two pins are concerned, it is considered that the current flows into one pin, and goes out from the other. 

This has to be known prior to simulation in order to correctly build up the matrix solver. This is why the currents may appear as opposite polarities in the same branch. 

The solution is simple, as mentioned by @dampmaskin. For more than two pin elements, it is considered that the current goes in the pin, for all pins.