Your 3rd one is actually how his Passive and Q work. I will pull info from League of Legends Wiki page for Master Yi. This is the link to his Wiki page --> http://leagueoflegends.wikia.com/wiki/Master_Yi I'd create a word link I can't seem to figure out how to do that.
First off is his passive: Double Strike
After landing 3 basic attacks, Master Yi's next basic attack within 4 seconds strikes twice, dealing 50% AD physical damage which applies on-hit effects and can critically strike.
His Q: Alpha Strike
RANGE: 600
COST: 70 / 80 / 90 / 100 / 110 mana
COOLDOWN: 18 / 17 / 16 / 15 / 14
Active Master Yi blinks to the target enemy and up to 3 consecutive nearest enemies, becoming untargetable in the process, deals physical damage to each of them, increased against minions and monsters, and reappears next to his primary target.
Alpha Strike can critically strike, dealing 60% AD physical damage to all enemies, modified by bonus critical damage. Basic attacks reduce Alpha Strike's cooldown by 1 second.
In other words: Working as intended. It's because Devourer (and Sated Devourer) both increase your attack speed by +50%. Making your Passive go off more often and letting you use Alpha Strike more often as well. Make sense? Side note: Sated Devourer just puts it into overdrive on how fast they are able to be used again due to the Phantom Hit passive of Sated Devourer. Hope this helps!
