I don’t know why it happened, but I can offer a solution:
If you’re on Firefox:
- Open Javascript Console (press f12)
- Click the button that looks like three rectangles in the top right and select the only other option
- In the console, enter
player.layers.intro.messages = 0
If you’re on Chrome (or 90% of other browsers):
- Open Javascript Console (press f12)
- Click the word “top” in the top left and set it to “index.html”
- In the console, enter
player.layers.intro.messages = 0