I'm guessing they don't have a 30% drop rate like a regular hard node? 8 runs and zero bonus shards.... The chances of that are 0.019% or 0.00019 (70% chance of not getting one, 24 times) Come o...
I agree, the drop rate is way below 30%. I used 3 refresh everyday during the event and barely got 20 bonus shards in the end. Same with guild event tokens, 3 refresh every day and got less than 400 tokens in the end... Double drop would have been so much nicer than this.