Dasie: Hello, I know this post is very old at this point, but I was having the same issue, so if anybody stumbles upon it they will hopefully find the answer
The solution that worked for me was loading a save file in which the gallery tickets were collected, then choosing Quit to come back to the main menu. This way the game recognized the Gallery was unlocked and it loaded properly
Yup, that one works, but you dont even need to load a specific save file, just go to the autosave and quit and try to enter to gallery, it worked for me