Botanicula- Sun Element Disc disappeared/did not register

I found the room and acquired the sun disc, my last of the star, rain, sun and plant discs you need to talk to the pacman guy. I walked through the rope room and grabbed it, but now it's not showing in my inventory and I can't move on. Did this happen to anyone else? Game developers aware? I literally can't play anymore.

This is a bug.

This is a new one, but similar ones have been reported in other questions and comments:

• Animation keeps on repeating (How can I fix a terrible bug in the middle of Botanicula?)
• Game is buggy in full screen (What do I do with this cone?)

and I personally have had similar but different unreported issues with the game playing automatically and having the animation repeat until the game was restarted. They are few and far between, but they happen.

Make sure to save often. There are six slots -- just enough to save at the end of each chapter.