Having difficulty with flat pattern

Okay, I derived this part as a surface body, thickened to .120" (my sheet metal defaults are the same,) and then create a flat pattern. All of my other parts have flattened out just fine and transferred into a .dxf file and opened up fine in autocad. Why won't this one flatten out? It wouldn't be that big of a deal, except I can't dimension the part (angles) to redraw that section in autocad.

Top Rail.ipt

In this image you see there is no bend radius on the left where there should be like on the right.

There are other bend problems on the part.

I mentioned ealier that I missed something.

1. Make sure the large arcs are tangent on both ends (in the master file).

2.Do not add the small fillets until after deriving and deleting the unneeded surfaces. (and there must be a fillet at each bend before thickening).

Here is the other bit of garbage

Okay JD, I was able to get the part to flatten out. I went back to the master and created a radius for the front bend and I added two fillets to the part and the fillets are what made the part flatten out. Why did I have to add these fillets? Is this something I am going to need to do everytime...I didn't add them on my other derived parts.

Alright JD, I am back at it again and finding difficulties with this. I shortened my drawing up and recreated all of my parts and flattened them all too. I am having problems with my bottom flattening all of the way and I can not find where the issue is. I derive component, delete faces, thicken to the right size, and flatten. I did not have an issue with this one particular component previously; it was the top before. I figured the top out; there was unnecessary bs. Shoebox frame 40.ipt

Bottom Rail 40 attempt.ipt

Missing fillet and ALL arcs must be tangent (constraint) to connecting entities.