I was practicing a bit and well now I ran into this problem, I have finished modeling this practice piece and now I want to add a fillet with the selected lines, the problem is that if I put a value in the radius of 3, the fillet causes an error, and what I don't understand is why with a higher value like 4 or 5 it works fine, even with a lower value like 2 or 2.5 or 1 it works perfectly, the problem is with 3 or 2.9. Even a value of 3.1 works fine. I really don't understand where the error is. I attach images.