When the monster appears outside Elsa's window, it casts a
nearly full-body shadow on the library wall, with one arm fully visible, but in the close-ups of the monster the arm in question is obscured behind the window frame. Later in the same sequence, Ygor pops up over the monster's shoulder, yet the shadow cast seconds later shows only the monster.
When Elsa is reading Dr. Frankenstein's notes, we see flashbacks of the monster being created, superimposed on the screen over the notes. When Elsa gets to the part of the notes that reads, "And now to find a brain", the flashbacks have shown the monster charged with electricity and brought to life and although in proper history, the brain was put in first the flashbacks are meant to be Elsa imagining the creation of the monster. Having never known about the monster she would not have known that the brain was first.
The first time we see the close-up for the wall plaque for "Dr. Frankenstein - Diseases of the Mind" outside his "mansion", it is hardly in such a place. If you look close to the left of the sign you'll see a ladder, wires on the ground, palm trees and a station wagon type of car.
The dramatic shadow cast by the monster's hand when first
discovered by Ygor in the sulfur pit comes from a light source completely at odds with the overhead light shining down into the sulfur pit in which we see the monster encased.