I know that the @YouTube algorithm screwing up is no news but can someone tell me why while subscribed to ~400 channels the newest video I’m seeing on the homepage/ recommended section is from 3 weeks ago? & half of them are ‘watched’(red slider on the bottom) ? 
@TeamYouTube
Could you try signing out of your account and signing back in and check if it makes a difference. Also, try switching networks, WiFi to cellular and vice versa? Keep us posted.