Hello, any changes that take place after you generate the campaign will not be included in the campaign. So in your example, the users assigned to the role during the one week period will not be included in the campaign.
It depends on how have you configured the Campaign. If you set the Campaign Generation as Scheduled (as might be your case) then the data is updated at the time of Preview Generation
Any updates to roles and entitlements prior to Preview Generation will be included in the Campaign. However, once the preview is generated no changes will be made as mentioned by @vkashat