Tavakai Crystal Cleave seems to do more damage than intended

See clip below:

https://streamable.com/1148eo

There is a frame or two were I sit on 1277 hp before the rest dissappears.
Maybe a shotgun effect of sorts?

At the time this character had:
1700 hp
600 armour
2000 evasion
1600 deflection (46% damage prevention)
10% damage taken from mana before life
10% damage taken from companion before you