Hey, so I usually play Sedna and use my heal heavily to support my fellow teammates. The bug I'm experiencing has got to be one that's known, but I figured posting about it might bring a little more attention to it because it's a real game-changer.
Anyway, frequently I will attempt to use my heal on a teammate in a battle and when i click my teammate, Sedna simply stops moving, doesn't cast anything, but faces the player. No abilities can be cast until I move off of that spot, then try again. I've had times where I've clicked a teammate three different times, selecting the ability each time, and the bug prevents the healing from occurring. This costs me kills (and gives the other team kills) ALL THE TIME in games. It's not a matter of me being stunned or something like that, I'm not a complete noob and I know when I'm stunned and when I'm just bugging out.
The bug is sporadic, it doesn't happen all the time, and I'm not sure what exactly prompts it. I do know that the only solution is to move, then try to cast again - by which time my teammate is frequently already dead.
This needs to be a priority issue for an upcoming patch, because it really really impacts the effectiveness of Sedna (though I still think she's clearly one of the better DGs)