We are having the same issue.
If I use the "test your copilot" functionality it uses the knowledge sources. Once I publish it into Teams and question the bot there, it gives generic answers without leveraging the defined knowledge sources.
Here is an an example
Question "what is ABCs backup policy?"
Teams published Copilot Bot
"ABCs backup policy outlines the procedures and protocols for ensuring the safety and integrity of data. While I don't have access to specific internal documents, a typical backup policy might include the following element"
Test your Copilot response
"*ABCs backup policy aims to safeguard information assets, prevent data loss, permit timely restoration of information, and manage backup and restoration processes. The policy covers different roles and responsibilities, defines rules, and outlines backup procedures for systems and data, including Office 365. It involves using ABC software for backups, maintaining online and tape backups, and ensuring data integrity and availability "