Shuffle vote considers 50%> majority that includes still connecting players. Very often people want to shuffle at map start, but its hard to get a vote through when the vote expects joining users to contribute to 50%.
This is another symptom of how much better gameplay would be, esp. in sw and execution, if we had an automatic player shuffle after map loading and a few min of warmup.
Im pretty sure im not alone in saying that a few min warmup are worth the wait to get a proper sw game going, which is so hard now when one side often starts with 2-4 less players