We do get this error in one of our environments in default folder. The license clearly says we can use it for troubleshooting and UiPath understands that we cannot purchase a dedicated studio license and have unattended license at the same time and when we have to hotfix bugs in production, we require studio access.
As you will notice, you do not need any license, your studio will open and you can edits workflows there. Just ensure you use it for troubleshooting and not developing workflows in the production environment.
If you are using default folders and have purchased studio / studio pro then you just do what is necessary. Do not worry about the license warning, there is no other alternative, which I / we known of.
Let the license be allocated as it was earlier. Do your required edits even if you get this warning. It is after all for troubleshooting purposes.