Simply supported beam moving under symmetric load

Hi,

I have an I-beam that is subject to two downward loads at both ends of equal magnitude (1893.75N). 

It is also being supported by two upwards loads (ie. a roller support).

When I simulate them, the beam looks to be moving to the left which does not make any sense, given the fact that both loads and supports are symmetric. I didn't expect it to be translating, can anyone provide some insight as to what is going on here?

The picture attached is what it looks like afterwards

Thank you

SolidworksSimulation