Its one of 2 weaponskills in the game in which the incap requires you to be in a different position than the added effect (And therefore the combo continuance)

Specifically...
To blind an enemy with Concussive Blow and combo into Simian thrash, you have to execute CB from the right or left...
But to incap the head of a MOB that can be incapped... you need to execute CB from the front...

Not game breaking... not even a big deal.. just interesting that you have to choose between the 2.....

Could it be that it would be over powered to incap the head, blind the target AND also combo into Simian Thrash? Or would it just be too easy to Pummel from the front, CB from the front, Simian Thrash?
I can see the logic in that... just wondered what the punchilist community thought about it

(In case you were wondering, the other WS that has this issue the MRD "Path of Storm")