This has been a long standing issue, I don't know if they can do anything about it.

One simple 'workaround' would be to have the game refrain from redrawing equipment while your cursor is on them. Once your cursor moves away, it would be free to draw it, or wait until the next change, either or wouldn't affect healers anymore.

I agree wholeheartedly with this change though, sometimes I target a character, by the time I actually push the macro, he disapears, losing focus. Sometimes the timing is so terrible that I end up wasting MP and recast timers on myself instead. Or on someone else that decided to cast on me (not having a target makes you auto-target the one casting/attacking you).

Similarly, when a character is just 'outside' of the targetting range, you can still target them for a split second, but it resets you to directly. Why can't the game either skip them or target them? I use controller arrows to target my teammates often (up and down on d-pad), and when trying to get to the 6th party member, if the 3rd one is at such a range, it keeps disrupting it and returns to me instead.

I don't remember if you lose focus when using <ST>, but that's not a terribly good solution either as it doesn't make it easier or faster to target the one you want. Keeping your tank in target is more efficient, except if he's blinking constantly.