Charged Staff missing Lightning Tag

Seems like Charged Staff skill gem should have the lightning tag, as it adds and does lightning damage.

This is a bit of a pain point because Lightning Mastery would be a big deal to put on it (would add another 24 flat damage at 8 charges to our artacks), but we can't at the moment due to missing tag.

Could we get clarification if this is a bug or intentional?

Bump - still a problem.

Thought my game was bigged and crafted a few gems of the skill, couldnt work out why I couldnt socket lightning mastery.