Frequently when in Glint giving the party boons then swapping to shiro the energy drain is still there. If i manage to swap back to glint my upkeep skills are still active.
Happens a lot since the latest patch
I'd like to point out another facet bug here which I believe is related: it seems that if Glint is your current legend when the fight begins then none of your facets will work correctly until you swap out of Glint then back in. In addition to the problem mentioned by OP, another one is that upkeeping the facets will only apply the boons once instead of pulsing them out every few seconds. This means that you're spending energy to upkeep facets but they're not doing anything (outside of trait interactions).
I think I have a workaround to both these bugs until they're fixed. First make sure your other legend is active during the ready-check countdown. Then once the match begins, or during the pre-match countdown, swap into Glint. According to my testing your facets should work correctly after this.