The UI of this event shows the option to make use of some not well identified 30% and 50% discount voucher.

It's 18 months that i play this game and those items never appeared once when this event was on live.

The very maximum discount voucher i saw for this event was a 20% one by recharging 30k+ ingots.

Since those items do not exist in our version of the game the fact the UI shows the option to use them is a bug.

P.S. I'm blatantly ironical... but the fact they don't exist and they never existed so far is a matter of fact.