This was resolved in version 0.11.52 - 5th February 2023

Impacts version 0.10.24 and below

Some players may experience an issue where a Level 8 or above Pond no longer produces Water Droplets and are unable to complete daily tasks.

This issue is a result of another issue with the serum item. We’ve been investigating this issue and our engineers have now found a fix that has been rolled out. Please upgrade to version 1.01.08 or higher. For help updating the app, please refer to How do I update my game?

We’re sorry for the inconvenience and thank you for your patience.