Alpha slot Cardiac- Self damage
I remember some talk about this being a problem with burn or some fire blaster power.
Edit: That said, I have Cardiac boost on my Tanker and haven't noticed a problem at all, but my tanker is invulnerability, so it's not precisely comparable.
http://boards.cityofheroes.com/showthread.php?t=246079
It seems that a Burn keeps breaking.
Scratch the alpha slot part, burn is doing self damage to all my /fa scrappers, it just isn't happening every time I use burn.