Apex derank bug?

Hello all

I was playing ranked and i've passed the trials to reach diamond4, after that i have lost some games reaching 18 ladder points, with 18 lp i lost a game, i should have 3 attempts with rank protection before deranking but i deranked to platinum1 at the first "no points" game lost, did anyone have the same issue? Is it a bug? Is there a way to have my rank back? Thanks