I was wondering whether there is an explanation why Qui-Gon's body does not vanish right away after he is killed by Darth Maul!? Obi-Wan's and Yoda's bodies vanish right away, while Qui-Gon's is burned at a funeral.
1 Answer
Qui-Gon's body didn't vanish because at that point, Jedi didn't know the skill to be the one with force (If you take Legends into account, the skill was lost).
Later in Episode 3, Qui-Gon's force ghost learned/re-discovered that skill and told it Yoda. Yoda taught that to Obi-Wan. That's why both were able to vanish at the time of their death (you should note that Obi-Wan's body vanished before Vader's lightsaber touched his body).