Solid difference + multiple sweep

I’m trying to substract object B from object A.
Object A is a solid CUBE, object B are multiple sweeps.
I’m using “SolidDifference” but I’m not getting correct results and I’ve tried everything I thought off.

Here’s a screenshot of my problem.
I’ve highlighted the (circle) sweeps which were supposed to be cut out of the top surface of the box - but the whole upper surface remains closed, without the cut. Even though bottom half of the pipe is visible if you scroll inside the volume of the box.

I’m completely lost and I really need help solving this issue. (14.2 KB)
3_5.3dm (12.5 MB) (14.2 KB)