hologram mechanic not respecting yoffset in location targeter

MM 5.4.0 28c6b0f1 || Paper 169 (1.20.1) When using this:

Skills:
 - holo{text="Test";time=100} @selflocation{y=2.6} @self ~onSpawn

I expect it to float above the mobs head. Instead this happens:

Nothing suspicious in MM debug: