You need to swirl it around again before you decant. When washing yeast you should only wait 10-30 min before harvesting the liquid. The short rest allows for trub to settle but still leaves viable yeast cells in suspension.
Overnight, particularly at cool temperatures drops everything out of suspension. While there are some yeast still left in the top/left/amber portion you would be discarding many more that have already settled.
1°: Graham's English Cider, Cider ; Conditioning: Blackberry Melomel, Banana wine, Cider, Orange/Clover blossom mead, Cyser, JAOM, In like a Lion RIS ; Drinking: Cider, Vanilla Porter, Blackberry Melomel, In like a Lion RIS