Weird looking simulation - Did i messes up with fixtures?

Hello guys!

I have a very very simple beam and have to check it for buckling.

Results "by hand" went ok, but when i simulate it, i'm having some weird results.

Did I mess up with fixtures?

Its a simple beam (H150 x 1/4" thick) with 2 steel pins of 40mm on the ends. Beam will handle a 148KN compression force.

I did a hinge fixture in the beam holes.

Force (148KN) is aplied in both holes (should i have done half force on each hole?)

It has a 500mm steel place on both sides for reiforce (I did the extrude with merge option, should be any different to use SolidWorks weld on it?)

SolidworksSimulation