Rank rainbow six siege

On the solar raid Y7S4 season I was emerald 4 and on the site it tells me that my max rank is platinum 1 I do not understand

Unfortuntely there is nothing we can do to retrieve that. You need to make sure to update your profile before every new season starts.

But what is the reason to update my profile as you say I have a friend who never goes to the site or the application and it shows him that he has finished emerald 4