Cross Punch not doing full Containment Damage

[Uno]

I used Cross Punch on a mob that was held, and got this result:

 

Your Cross Punch hits PPD Enforcer for 26.08 points of smashing damage!

You clock PPD Enforcer for 15.6 points of smashing damage!

 

 

For some reason it is not doing full double damage with Containment. Both Kick and Boxing did full double damage, so I am not sure if this is intentionally reduced or a bug.

[Uno]

Spring Attack seems to have the same issue.