Board Game Arena

I've had a couple games recently where I purchased the sector 8 2x reward card, and I'm not sure if I'm misunderstanding it's function or if there's a bug.
As I understand it, gaining charge cubes is a reward for activating a sector. The 2x reward card should thus be able to be spent to gain 2 charges instead of one on another sector. The game allows the 2x reward to be activated for sectors with charge cubes rewards, but then doesn't do anything.

I've not had that issue myself, I've had success using the 2x card to get 2 rather than 1 cube on another card.

I guess I'd suggest be careful to select the 2x cube before selecting the other card?