Sisters of Garukhan did not reward +10% lightning res after defeting them.

Same here, saw the text in the chat though, so I guess something triggered but the effect hasn't been applied to the Character sadly.

Update:
I wrote earlier that they didn't give me any resistance, but earlier, I completed this quest on the usual difficulty.. When I completed it on the Cruel difficulty, only then did they add resistance to me. So the bonus works, but it needs to be completed in both difficulties.
I took off the items and noticed the resistance bonus, so it definitely works.

Same for me. I have 36% lightning resistance and it is all from gear. Ensured there are no remaining MOBS in the map; /remaining shows zero. Cleared all fights.

Where is my +10% lightning resistance?

Just for yall wondering and thinking this is a bug or something. You actually got 10% resistances since in ACT 2 is -10% all res debuff and when u unquip all your gear u should stay at exactly 0 res after compliting the shrine. You get the 10% res buff on clicking the shrine not on clearing it.

Was going to follow up if it helps I didn't notice an item drop or any in-game announcement of said bonus but on the quest map (at least for Xbox) you can pusht the right joystick to scroll through the various enemies that award you bonuses along the map and when I went over this one I did have the resistance added. Just thought there'd be some "Quest Complete" or something popping up as I backtracked over that map twice to make sure I didn't miss any of them lol.

Same for me
Twice. On both normal and cruel :(