Hey there,
It seems like if you are using NON channelled flurry while moving (holding move+attack buttons at the same time) it skips the third strike. You can test this if you spec into Vile Tactics node: you wont apply any poison res shred and phys res shred from this node while moving. Also strike skipping is quite obvious visually when using a bow.
Is this intentional or it’s a bug?