I fought an Akira in the Cherry blossom stage and the same thing happened. Helena's pp4k is supposed to knock them away, but in tag it acts like a relauncher. Same thing happens with her BT string that looks similar.(forgot notation)
Best thing to do would be to test it in the dojo or versus with a friend, if possible, making sure all the variables are the same and rotate through every stage. See what the results tell you and report it back here.
Err...hopefully this is was just a strange glitch, and reflective of the patch as a whole. Some characters can do some pretty high damage combos by themselves in tag.
For example, Sarah can get over 100 damage off of a raw NH launch, and Kasumi can get over 120 off of NH 236T.