Having just promoted my characters and started levelling them again, I've noticed a weird glitch with the Retaliation characters. The first time you go to level their powers upon level-up, they have higher than normal points to spend on powers. Backing out, selecting a non-Retaliation character and then going back to the Retaliation character removes the spare points. If you spend the extra points, they do stay assigned, but the next time you enter their power menu, they'll have negative skill points, with levelling them up further adding the extra points again.

It's a weird glitch, and technically I believe you could use it to completely max a character's skills out, but that sounds like exploitation to me, so I've been avoiding the spare points where possible. I only noticed after I nearly maxed my Volus Engineer's skills out at level 11. Cancelled the level-up post hate and backed out, and found the solution I mentioned above, though I'd already spent some phantom points on an earlier level up, so I'm not playing him until the skill point debt is sorted.