Closing as won't fix. The solid behavior is not meant to be used with movements. When you move a solid like that, you're effectively teleporting a solid in to another movement, which is set to not overlap solids. When the behavior finds itself wedged inside a solid it's not supposed to be in, it resorts to a sort of emergency "get me out of here" avoidance which looks for a nearby space and positions the object there instead. That doesn't always move in a predictable direction, hence the inconsistent direction. So this is actually working correctly, given the design of the engine.