When having solara out in blood more in the middle Patch and 40% spd. Normally she hits bosses 2 times on the bottom side and 3times on the upper side. The last hits were really close at the end. But if I am not mistaken I saw her hit some bosses once on the bottom and only twice on the upper side. So either movement of normal bosses or attack speed is not consistent.
I will may show this on a replay if I find a good one.