Shattered Kingdoms

The skill doesn't seem to be working properly since the last time I played. Head butt either misses 90 percent of the time or it gives a hit message saying the NPC is stunned, but they continue to attack and cast as normal. It seems like a bug but I can't be sure. Was the skill changed/altered?

Does not appear to have been changed since 2012:
Headbutt update

However, head butt is a form of paralyzation. That was changed in 2017:
Paralyze update

I can't say for sure that change didn't negatively affect headbutt, but in reviewing it, seems like it should be the same or better.

That's my mistake. It appears as if the damage message has changed and it threw me off.

It's actually the blue message that says 'knocked out' that I didn't see until today while doing more testing.