I figured out how to fix the error. I'll prepare a new version of the kit, but in the meantime it can be fixed manually by changing the source (game.zip) as follows:
- Open the file assets/rooms/collector.tuba in a text editor
- Find the line that says name = "new_poster"
- Modify the line above so that baseline is -1 instead of 0
- The final result should look like this https://pastebin.com/jSj970bH