This is for dragonflight not classic.
#showtooltip
/use [harm][@targettarget] Holy shock
This macro has worked for me for years now but ever since dragonflight it doesn’t work. It will always just heal whoever I have targeted. I’ve tried every variation I can think of and have searched and searched to no avail.
If anyone has any suggestions it would be greatly appreciated.
A) make sure you’ve got the macro on your bars.
B) what’s the goal with the targettarget? Its setup to do both enemies and allies currently.
I only want holy shock to hurt my targets target. I don’t want it to heal my target.
I use the same macro for Judgement and Hammer of Wrath which both work. Holy shock use to until Dragonflight.
#showtooltip
/cast [harm] [@targettarget,harm,nodead] [@none] Holy Shock
/stopspelltarget
Still heals my target instead of harming the targettarget. 
I appreciate you trying to help.
What keybind is it on and what is your Self Cast Key set to?
Shift - mouse button 4, Tried swapping it to different binds, same thing. Alt is my selfcast.
Ive also tried toggling off auto self cast. Tried many things nothing seems to work.
Any other workarounds you can think of for this?
Think its jus some bug that needs to be fixed.
I think all you can do at this point is report it as a bug.
I tested Elvenbane’s macro myself and I’m getting the same problems. (Friendly target with an enemy targeted causes it to cast on the friendly target.)
So, I tested that macro on my priest with Penance. In that case, it works as expected. It casts on the friendly target’s enemy target.
So, it looks like there’s most likely something weird happening with Holy Shock itself.
Edit: I also tried it with @focustarget and @mouseovertarget. Neither of those worked with Holy Shock either.
There was an issue in pre-patch were mouseover Holy Shock was casting on target if you had one, the fix there was to do the /cleartarget /targetlasttarget shenanigans, but that obviously won’t be effective in this case.