There could be something I am missing but I am fairly sertain it is a bug.  When Tekteon uses his A3 it does not always place the poison cloud and taunt buff on himself.  Sometimes he only places the poison cloud, sometimes he only places the taunt, very rarely neither, but most of the time it works as the skill reads and places both.  He always places the shield on all allys.  I have not had an issue with him placing the shield buff.  His A3 still grants an extra turn but I can't figure out if I a missing something that could be denying him placing the buffs on himself, but I am fairly confident this is some kind of bug. I know for a fact the buffs are not being denyed due to a block buffs debuff because this issue has occured when he as no debuffs at all.  I have only used Tekteon in classic and live arena.  There have been times wher this lack of buff placement on himself has happened in both.  I play on mobile and PC and it has happened on both.