I'm so sorry for the delayed response! So the specific bug will be potentially hard to recreate.
In the Mushroom painting, I had collected all but two mushrooms and was going from the 3rd room (with the big mushroom who is lonely) back into the second room. I hugged a little to close to the edge of the tree tunnel and when the scene/camera transition occurred, the player model seemed to clip into a decoration mushroom in the tunnel. No matter how I rotated or moved, I could not 'unclip' myself. Fortunately, the load feature got me back in quick.
I suspect that it was not a stateful glitch and more just unfortunate geometry and physics interactions.