Maybe they hadn’t perfected tailoring clothes, and tried altering the lengths of limbs.
Orrrr, maybe they couldn’t find all the original parts of several people after some horrible demise.
Maybe that was all the parts they found after a group of friends got attacked by wolves, so they buried them together.
Maybe there was a terrible battle, and they had enough hacked-off parts to reassemble two warriors. Why? Because they could.
Maybe they were criminals, and they were reassembled from parts in order to cause confusion in the boggy underworld, so they would be rejected from the afterlife.