In an arena battle I saw my opponent suddenly start bleeding, even though there was no notification that the bleeding damage had been inflicted. I've included a screen shot showing the first sign of bleeding. As you can see there's no notification like 'Bleeding: 12', is this expected behaviour?
PoW-bleedbug.jpg
If the Devs need to check this battle it was at Jun 08 10:29 am server time, between Empusa and Olveek in the Elite bracket.