I've noticed that my striker's 3rd shadow hit does slightly more damage than regular shadow hit. There's nothing on the wiki about it, so I thought I'll create this to let you know. I was testing it in Guild Training Hall and it seems this increased damage is only in regular combo and not in the charged one. Also, I could not get the final shadow hit with charge. It looks like there are regular 8 hits (4 normal, 4 shadow) finished with one final swing without shadow after it.
Do other swords from Cutter line behave similarly or is it just this one?
I have studied this in detail. Then I wrote the wiki text that you're talking about.
You are probably wrong. Maybe the third hit seems to do more damage, because you've poisoned the target, decreased its defense, and thus increased your damage?
Maybe you could give a video showing the effect that you're describing, please.