After learning the Lumos spell Harry proceeds to a challenge map. [In walkthrough videos](https://www.youtube.com/results?search_query=Harry%20Potter%20and%20the%20Philosopher%27s%20Stone%20PC%20lumos) it can be seen that the last platform created with the spell is at the same height as others, but in my game on the ground level:

[![Lumos challenge issue](https://i.stack.imgur.com/MuTID.jpg)](https://i.stack.imgur.com/MuTID.jpg)

Harry can't reach the doorway (upper middle in the image) by jumping from the edge of either podiums.

The last platform floating correctly in the air (from a [walkthrough video](https://youtu.be/YoG05S4WoFQ?t=11m47s)):

[![Lumos challenge](https://i.stack.imgur.com/LlEtX.jpg)](https://i.stack.imgur.com/LlEtX.jpg)

I have reloaded my save and restarted the game. Sadly the progress is saved in one slot and because the game saved in the middle of this challenge the level can't be fully reseted. Can the issue be solved without starting a new game?