Attacks or abilities consisting of more than one action are failing to execute fully. The first action is performed, the game freezes for a few seconds and then the turn ends without the rest of the skill being performed. This is true of multiple heroes. 

In the arena: Elhain will use Lightning Arrow; The normal behavior is that she attacks a single enemy and then all enemies. She attacks a single enemy and then the game hangs for a few seconds and then she never lands the attack against all enemies; the game proceeds to the next hero's turn. 

Mausoleum mage has a skill that should remove all debuffs from all allies and then heal them. The amount of healing is based on how many debuffs were removed. What's happening now: he removes all debuffs, the game lags then nobody gets healed.

The clan boss will use an AoE attack followed by a few seconds lag spike. When the game resumes, one of my heroes drops dead even though they had plenty of health after the boss attacked.