Well, it looks like that since last Friday...
A whole week is enough time to update the ranking, I think.
I sent a 1:1 and I got the following answer:
At least it seems like it is not working as intended.
Also, before the last maintence I got my first Tombeth Seal and my ranking changed to 28. I got 20+ seals after that and it did not change anything. I gave up and my ranking did not drop.
Maybe I am wrong but this ranking thing seems weird for me.