Yep, that beta build had a bug. You are supposed to use your Feedback tool to report it but since they already issued another build that fixes it there is no need to at this time.
Go to Settings > General and scroll down to make sure you still have the beta profile on your iPhone. If you do go to Settings > General > Software Update and install the latest build. You won't see that message anymore.
If you do not have the beta profile anymore go back to the Public Beta site and re-enroll and put the beta profile back on your iPhone then update as I said above.
If you want to roll out of the beta program follow ALL the steps here: How to uninstall iOS beta software - Apple Support
Or wait until iOS 14.2 is released and install it.