The tooltip says, "this ability always goes first." 'Deflection' is now in the same category as 'surge' and 'quick attack.' This means that if you use deflection against another "...always goes first alibity," the speed of both pets determines who goes first. It's working as intended.
Flayer Youngling and Idol were nerfed hard.
As a side note, Flayer's 'Focus' abiity is bugged in 5.2: it does absolutely nothing.