The issue appears to be that RayTraceBlocks does not account for non-full blocks being in the way, whilst Hypixel does.
I would like to contribute and search for a potential fix.
// src/main/kotlin/gg/skytils/skytilsmod/features/impl/misc/ItemFeatures.kt : onRenderWorld (line 779)
val obj = mc.theWorld.rayTraceBlocks(vec3, vec32, true, false, true) ?: return