How to get Druid basic attack quality buff as a skill gem? (gemcutter not working)

There is a quality buff for Druid basic attack skill like Rend for Wyvern. It boosts 10% lightning damage for the basic attack. However, there is no way to boost the quality as the game treat the skill as normal attack. I tried using the gemcutter on it as you would for normal gem but it doesn't work.

The weapon is not corrupted and also at 20% quality.

Can someone from GGG give an explanation in terms of how to get the quality buff and how does it work with changing up weapon and form? Are we supposed to spend gemcutters every time when we change a weapon!?

Bumping this, really want my 10% lightning buff on Rend.