After Kelly is supposed to be hypnotized and Dr. Slavin moves to the cabinet, the shots of Kelly opening her eyes are flipped in order to make her look in the right direction. Notice the lampshade in the background switches from left to right in three short close-ups, then back again.
When Kris is trapped inside the sauna, she has to stand on her toes to look out the window in the door. But when seen from outside, she is able to look out much easier.
When Kris is looking for Eve Le Deux's manuscript in her room, there is a closeup of the vase with a flower arrangement. When Kris removes the flowers from the vase and finds the manuscript it is a completely different flower arrangement.
Kelly needs to break the glass of the steam room door to get inside to free Kris. Kelly and Kris, the latter who would be barefoot, walk right on where the broken glass would be in exiting the steam room, neither flinching about stepping on broken glass.
Miss Ingrid insist that everyone at Springtime is to be referred to by first name only, but seconds later she introduces a guest using both first and last name, Miss Norma Powers.
During Kelly's hypnosis session, instead of pressing both the record and play buttons simultaneously - as is necessary in order to record with that type of cassette recorder - Dr. Slavin presses only the play button.