no glitch there, sadly, when u loose many games in a row your attendance is lowering gradually until 1k or 2k.
I can strongly confirm this.
When i deliberately tanked last season(i am again) i noticed that.
My solution was friendly matches. I played 3 or 4 friendlies a day winning them all and then loosing my league game,i could keep a constant 210k-211k out of 260k