Drop grade (Gwent: The Witcher Card Game)

Hello!
I can not understand... now if you lose decreases the rank or is it a bug of the last update?
I was 16, and not missing a single victory to 15, did not play for two weeks and then went, the game has offered to date. Updated, played a match, lost and I dropped from rank 16 to 17, and without any mosaic, as if just took a new rank.
A very strange phenomenon.
Or the rank you can always lose, tell me, please.