Windows: I'm having an occasional targeting issue since starting the 64-bit client. So far it has only occurred in TFs and Trials: I'll tab to target successfully, but as soon as I try to use an attack or power using the number keys, my target will switch to the most recent PLAYER CHARACTER target selected.
This just happened in a TF, yesterday. Logging out and back in did not fix the issue. It makes attacking with the number keys impossible while it's occurring. Essentially the powers will not activate by number key, and will only activate by clicking on the individual power with the mouse. I had to log out, switch to the 32-bit client, and log back in to fix the problem. I've seen this issue reported in the Help channel a few times. One person said they fixed it temporarily by alt-tabbing to their desktop and back in, but that didn't work for me in any of the 3 occurrences so far.
I've checked all my settings numerous times to see if I've accidentally deactivated all my number keys, but that seems not to have been the case.