Emergent bias occurs after some time when a product is launched and used in the market due to the continuous change in the environment of the product such as social norms in the world.
Example: A certain social media account plugin in an app might be useless when people stop engaging that social media tool.
How to prevent emergent bias
You can track:
The trends in the data and how your data changes over time.
How the conditions in the broader world change over time such as cultural norms, societal values or technological trends. Then understand how these changes affect your model.