Not that this is very helpful, but I suspect this issue is a real bug. The crystals have to be picked up and used in the correct order. First the charged one. Insert it into the discharge labrum beside the teleporter. This activates it. Then the other (discharged ones). Insert those into the charger. Then use the teleporter to go "upstairs" and insert the two into the labrums there. If you have two lucents in your inventory and didn't activate the teleporter yet, it won't work and you're stuck. I had to restart the whole quest to get past this. Annoying.
Not that this is very helpful, but I suspect this issue is a real bug. The crystals have to be picked up and used in the correct order. First the charged one. Insert it into the discharge labrum beside the teleporter. This activates it. Then the other (discharged ones). Insert those into the charger. Then use the teleporter to go "upstairs" and insert the two into the labrums there. If you have two lucents in your inventory and didn't activate the teleporter yet, it won't work and you're stuck. I had to restart the whole quest to get past this. Annoying.