According to this article Atlético Madrid has to play in the Europa league next year.
But Atlético Madrid finished last liga championship - La liga 2016-17 in the "top 3 qualification spots for Champions League group stage". And this year they are in the top 3 also. Why do they have to play in the Europa League then? Isn't qualification for the Champions League supposed to be the top3/top4 teams in La Liga?