seems that if I have “Boundless blows” for flurry and “Crimson shroud” unlock on the bladedancer tree, I only have a chance to proc crimson shroud for the first hit against any enemy. can get up to 3 stacks of crimson shroud if I spam flurry instead of holding to channel.
Unless its a specific channelled feature, Channelled skills only proc effects on the first hit when the channelling is started - this is by design and is not a bug. There are many such instances where a channelled skill will not do the same as spamming the same skill manually.
Not quite. If the thing is “on use” then yes, it will only proc when you start to use the channelled skill (such as the Crimson Shroud & Veil of Night passives for Crimson Shroud & Dusk Shroud stacks respectively). However if you have something like Lethal Cadence being consumed (20% - 100% increased damage when it gets consumed) then that will affect the entire channel if the channel is the third use. The Mage’s Preparation passive is the same, if a channelled skill is the one that “consumes” it then it will be affected for the entire duration.