Rem's heal burst only works once per Tag Along

[panvxv]

I am not sure if it is a bug or not but Rem's heal burst only work once.
Here is an image after I jumped from one Infernus to the other starting from right:

Only the first one received burst heal while others Health Restored. In the description there is nothing about Heal Burst only working once. I think it really punishes Rem's capabilities of a support.