Whenever I run into this puzzle where I can't stand on a platform that has a golden key (where the door spawns at the corner of the room) so I can acquire them all with Telekinesis before I use my potion of Levitation, I'm forced so spend a turn of Levitation acquiring the one key that isn't targetable due to line of sight/effect and can't make it back safely using just one Levitation Potion.
Is this by design, is there a better way to solve this puzzle, am I doing something wrong?