Finally, I noticed something bizarre. I finished the season in Gold 2, and instead of starting at Silver 1, I was moved back to Bronze 3.

I read something about this, but I thought it was related only to Survival mode. In that case (survival mode) they said that if you hadn't played any game yet in the new season, they'll move you to the right starting league. I don't know what happened for Wild, I started where I should have...