By default, when a new user is added in Signitic, it is directly switched to active mode and assigned to the main group of your main entity.
Therefore, if you have a signature for this group, the signature of this new user will be directly updated.
If you want to deactivate this option, go to My Settings then Connectors.
Then click on your main connector: Office 365 or G Suite. (G Suite in our example).
You just have to disable the option of automated user activation.