I some how made it so I can't cast Shadow Mend again after I cast it and Atonement is on my target. If I do this on myself and cancel Atonement, I can once again cast Shadow Mend. I did make it so bars change color when I put Atonement on my target, and maybe that somehow resulted in this problem. Any help is appreciated.
While in disc spec, I am unable to cast shadow mend for several seconds (10 or so) after my initial cast. It doesn't even show as an option on my left click during this time when my cursor is over the bar.