More Sig Move

So I got Sweep as the SM for my war Filbert Green...or so I thought. The first two times it triggered as sweep, then Stun, then sweep and now two consecutive stun. I have seen the odd off favorite SM being triggered, but never like this. I wasn't going to sink any points into Sweep, but now I'll have to make sure it's not Stun that is the primary. This ever happen to anyone else? I have sig move on 6 current glads and 2 previous ones and it has always been cut and dry with the favorite. It's a little curious and because I only have it at lv1 it doesn't trigger very often.

Ive seen it happen before but it doesn't happen very often~

So I added some points to SM to figure it out and when I ran his contracts this morning he did this in 20 fights:
Stun, Sweep, Sweep, Stun, Sweep, Blind, Sweep, Blind. It's so all over the map that I think I'll have to keep the skill. I think this is how SM should be in the first place, but this is super odd.

Ps I think it's sort of safe to say that Sweep is his move.