I'm sure a lot of people are getting this. I've seen it in another thread about Operative bugs.
I'm thinking we're not reliable for raid healing if we have a skill that has a chance of not casting. Too many things hinge on Kolto Injection, particularly TA. If Kolto Injection fails and TA falls off, we can't use Stim Boost (something we need up all the time), and we can't do Surgical Probe. It's also the strongest heal in the rotation, so if the tank is taking a good beating, can't rely on this to keep him up.
1/6 is about the average that I get. The worst consecutive times was 3 fails in a row where I was soloing a champion for a good 5 minutes when this got me killed.
Please share your report. Already had a "known bug" feedback with the bug submission.