Do you open Streamtime every day and have to switch user because it automatically defaults to someone else?
It's simply because the password is stored on your Keychain Access, once you delete it from your passwords it will stop Streamtime from automatically logging in.
For Windows, this is handled by the Credential Manager.
Go to search, type in Credential Manager. Click on it > Windows Credentials > drop open FMP > Click "Remove"*.
*This information may vary depending on the Windows Operating System that you have so please adapt above steps to your Windows OS version.