So far, no one has reported any problems that would prevent them from completing this third stage. But we can never rule anything out.
First of all, did you get to see the walkthrough of Josh's story?
It can be found on the game's Patreon page (now publicly accessible) or on the game's X profile.
Take a look there and try to follow the instructions to see if you've missed any important steps.
If it doesn't work, let me know so we can analyze how to help you.
Translated with DeepL.com (free version)