When talking to the High Lama, Conway sees the crutch next to the High Lama's chair and makes the connection between the High Lama and Father Perrault. However, when Conway first enters the High Lama's room, the long tracking shows the High Lama sitting in his chair but there is no crutch next to it.
Echoing the words of the critic, James Agate: 'The best film I've seen for ages, but will somebody please tell me how they got the grand piano along a footpath on which only one person can walk at a time with rope and pickaxe and with a sheer drop of three thousand feet or so?'
The goof items below may give away important plot points.
When Bob, George and Maria are leaving Shangri-La, they pass to the right of a Tibetan stupa. As per religious custom (then and now), they should always walk to the left of the Stupa, and never to the right. It could be argued that they did so out of ignorance, but Sandra is chasing after Bob and commits the same error. Surely she has been in Tibet long enough to know of this ancient custom and would never make such a careless spiritual mistake.
After George falls and dies, we see Bob picking his way across the wind-swept snow poking at it with his staff to make sure of his next step. He is obviously wearing a hat with a brim. In the very next scene, just before Bob falls, we see he is wearing his hooded parka again.