Originally Posted by Dorei0sama

It seems there is less and less life crystal rewarded (last event also around 5 life crystal).Normally it should be around 8 life crystal in ultimate map.

It's been pretty consistent since they started adding the life crystals to the event maps a few months ago (initially, we didn't get life crystals from event maps at all)
?-3: 2 LC, small chance to get another 2 LC
?-4: 5 LC, chance to get another 2 LC, very small chance to get yet another 2 LC
?-7: 2 LC, small chance to get another 2 LC
?-8: 6 LC, chance to get another 2 LC, very small chance to get yet another 2 LC

Some events seem to have a slightly higher chance at getting the 2 LC "extra" boxes, though it might just be RNG. Previous event, I seemed to get them around 30% of the time.