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).