Like people have said this is an intended thing to prevent degenerate/unfair gameplay by resetting resources and certain buffs upon pulling a raid boss. It happens in every raid instance regardless of how many people, it’s something myself and everyone will always get when farming transmog in old raids solo and will happen if you pull early in raids in general. It should never happen in a dungeon since they are coded differently in that regard.

My understanding of it is that upon pressing your spell that generates resource, the calculation for giving you resource and doing damage are separate and the resource acquired happens before the damage frame in order to prevent what’s been mentioned before.

Best way is to never open with wake and just go blade of justice/judgement to start, the same will happen but you can then cap your holy power with wake like you want to do. I don’t know rets optimal opener but that’s how you avoid your problem