Banners are being duplicated

Banners are being duplicated when removed using a pick with silk touch (apparently) using ax with soft touch there was nothing wrong.

When it is extracted by the pick with soft touch it generates an item with a strange name with black banner function and once it removes the new banner it finally takes on the name of the black banner. I have this image I hope to have said clearly if there is duplication I'm sorry. Thanks and hugs from Brazil.