OK, I searched the forum for the solution to this problem, but didn't find (or didn't understand) any possible solutions. I have an extrusion that I want to fillet. Please note that, if I select ALL of the edges, the fillet command works fine. But, I want to understand why the workflow I'm illustrating doesn't work.
So, I select some edges to fillet:
Then, I select the edges at the end:
And, I get this:
Huh? What am I not understanding?
Thanks, in advance, for your help and suggestions.