Have You tried to play with accuracy setting?
There is in Your model 0.0001, I tried to set to 0.001 but it allows only values from 0.005 to 0.5. I set 0.005 and regeneration fails on Trim 6 feature.
Now I cannot return accuracy back to 0.0001.
That's just the way it was sketched against the reference. When I select Tools-> Geometry Checks there are no errors. Can't see how that can affect the merge or can it?
I don't know but if look at the model there are some holes os small surfaces and may be the F46 and F27 don't connect or intersect.... I think the bottom of the blade should be coincident with the plate