I think it's a combination of crashing a lot in the first week, suffering from the rainy and cold conditions (which he really dislikes) in the Alpes as a skinny climber and maybe also some lack of confidence after such start.We will know what happened to him one day. This is obviously not his normal level!
At least, he managed to stay with the favourites far longer than in the Alpes. He was like the 20th last rider to get dropped, even though he completely blew afterwards.