Region union error

I’m trying to create a union from some shapes, but the output isn’t created the intended outcome. I’ve attached a .gh file with the error. Thanks
Region union (13.1 KB)

What is the intended outcome? Can you add a sketch to explain what you need to get as a result?

something like this, the bottom right corner is off, need to have a rounded finish

Not sure what the problem is it looks like this here:

I baked the result and moved the surfaces away from the original place.