I've discontinued support for the Gallery. It's an old system from about 0.5.0 version, and I don't have the time to update it. The darn gallery is bugged in a way I don't fully understand. I plan on reworking the gallery fully in a later version. As I've experienced it, sometimes the gallery works, and other times it doesn't. You might find that if you try it on another run it will work.
It's not something you did. Thank you for the report! <,< Sorry for the bug.