Hi Guillermo,
I tried the method in your tutorial on the images I sent you.
This is the result I got. Not sure if I did it right so I included the layer tab in the screenshot which shows my settings. The white is all blurred overlap including the edge of thinner branches moving with the birds weight. Perhaps expected?
Interested to see if your version looks the same. The birds in flight came out looking good where there was no overlap (2 small grey spots).