Lieutenant Love's Geist Schritt was waiting for Zeranic Vagabond's Sheath Sword, making it miss the mark!
You can avoid Sheath Sword (despite having ALREADY LANDED THE BLOW)'s Hidden Cut, despite already landing the hit.
This is rather obviously a bug, considering Hidden Cut's interaction with Cobra (in that you can't 'dodge' an attack that has already hit you.)
Eh? Geist shouldn't be triggering on damage instances, only when you are targeted with a skill.
Well, it trigerred whenever they used Sheathe Sword (for whatever reason). They were adjacent to the Kensei in question, so maybe that is why it occurred?
What probably happened was they used sidecut, which is an AoE ability, bypassing all geists but leaving all active as if they were not hit.
And then they used hidden cut. Which is a "targeted" non-basic attack. The target being everyone that was hit, technically not an AoE, so it gets caught by the geist.
Did you target them with Sheath Sword before using? I mean, the blue square that shows one tile is selected. If yes, that will (FOR SOME REASON) proc Geist Schritt, as you are targeting the enemy with it.
Sheath Sword has a 1 tile range, instead of 0 like let's say, Shukuchi, or Charge. It allows you to target the enemy as the 'range selection' points under the enemy's square, and Geist activates there.
The kensei likely accidentally auto targetted the boxer with sheath sword, since it has 1 range like a basic attack intended to let you face different directions, maybe it should target self like expanding ice.
Can confirm that this happened due to using Sheath Sword in one range against a Boxer with Geist active in order to proc Hidden Cut. Doesn't make much sense for you to 'send it off-course' an attack that was already made, or just sheathing your sword.