Found the issue, if I remove a gallery from a post and place it back, the configuration of the thumbnails are right!
Looks to me that the Gallery Settings – are not overwriting the configuration of already posted galleries.
here an example:
The first gallery was removed and put back – it´s ok!
The second one was inserted before I change my Theme, if I remove and insert again it will be right.
This could be caused by Theme or Plugin?