Summary: There are some instances where chamber blocking does not work correctly . The weapons will visually pass through each other with no collision. I've posted a few examples below in slow motion of the cases I found, but there could be more.
Media (Screenshots & Video):
Chambering the shaft of a scythe works, but the head of the weapon does not have collision when attempting to chamber it.
Similarily, chambering the head of a spear does not have collision, only the shaft.
Sometimes, chambering a sword stab does not work as well.
While these video examples are from the Full Invasion 3 mod, it uses vanilla assets and combat and I repeated the results in vanilla single player.
Media (Screenshots & Video):
Chambering the shaft of a scythe works, but the head of the weapon does not have collision when attempting to chamber it.
Similarily, chambering the head of a spear does not have collision, only the shaft.
Sometimes, chambering a sword stab does not work as well.
While these video examples are from the Full Invasion 3 mod, it uses vanilla assets and combat and I repeated the results in vanilla single player.