|09:47 am - Two times is the charm|
So, until LJ gets its 'revert to default icon in comments' glitch sorted out, the best fix is to hit the 'preview entry/ more options' button-- supposing you managed to keep that one as well-- and reselect the icon you want. (The preview reverts to default too, but once reselected, it stays reselected.) This obviously has it all over 'edit comment' in not sending two emails to your recipient, and is a nuisance only to you, not to everyone.
A big thanks to archangelbeth for the info.