As a person who makes games I can give you such an answer:
It sounds like you may have encountered a bug with the mushroom bricks in the chest. To resolve the issue, you can try the following steps:
Delete the world that contains the mushroom bricks.
Restart your computer to clear any residual memory usage.
Load a different world and check if the issue still occurs.
If the issue persists, try verifying the game cache through Steam.
If the issue still persists, you may need to reach out to the Obsidian support team for further assistance.
It's important to make sure you backup any important data before attempting these steps. Good luck and hope this resolves your issue!