I mentioned this in the Patreon notes, but yeah, there's a small catch to the gallery.
To make all the old scenes compatible with a gallery feature, I had to dome quite a bit of heavy restructuring, which means RenPy doesn't know you've seen some of the older scenes. So, sorry about that.
The scenes are permanent unlocks though, so you could start a fresh game and speedrun the locked scenes and then switch back to your main save.