Not new. The button on the Victory screen is “Skip” while the reward animations are playing, changing to “Continue” when the animations are complete; so if you’re quick on your controller you can hit A to skip the animations then A again to continue. Has been this way for as long as I’ve been playing 
(McDoubleDad’s explanation makes sense to me: if you’re super impatient – or gnoming – then you’re probably spamming A at end-of-battle to get through the Victory screen ASAP, and in 8.1 it seems there’s a new narrow window within which that button-press problems.)