So the granny event info has this in the Polish language version
It says that you get an uber for every gem purchased. EVERY GEM, not gem PACK. The way it’s worded it implies that if you buy say 200 gems, your teammates will each get 200 ubers.
Perhaps you would make this more consistent - either pay a chest per one gem or fix that caption (“Doskonałe skrzynie sojuszu za każdy kupiony pakiet”).