I am having a bit of a problem with the mission Assimilation and was wondering if anyone else had run into this issue. When the mission begins I have to defeat two spheres and a cube. At this point the borg begin moving towards rifts that have opened into fluidic space and I am suppose to follow them. Once I arrive there I have to defeat three groups of borg and three groups of undine. This is where the problem begins. After I open fire on the first ship and get it down to about half health, all the ships become invincible. Nothing I throw at them even makes a dent!! There shields begin recharging and they begin regaining their health. Even the other ships aren't damaging them.
I had this problem on another of my characters but after exiting the mission and coming back it worked fine. I have tried that on this character and it doesn't seem to do anything. I have even dropped the mission and tried picking it up again the next day! Anyone else had this happen to them?