Problem of inheritance of permissions on my sites.

Hi,

I have a farm Microsoft SharePoint 2010 Service Pack 1 (SP1) with hotfix for Microsoft Office Server (KB2536599) installed. The farm consists in two fornt-end, 2 back-end and a cluster DB with 2 servers.
We have 7 sites with a permit specifically defined for each site users, but for a while I'm reporting a problem of inheritance of permissions on my sites.
When I create a new user in AD and add the appropriate AD groups to access a particular site, I see that in other sites also gives permission.
The main difference I've found is that the sites that have given me permission indicates that the user is within a group, perfecatamente assigned, but for the other sites  that should not have access gives the following permissions, not including any specific group of SharePoint:

Permission levels given to NewUSER
None
The following factors also affect the level of access for NewUSER
Add Items  -  Add items to lists and add documents to document libraries.
Edit Items  -  Edit items in lists, edit documents in document libraries, and customize Web Part Pages in document libraries.
Delete Items  -  Delete items from a list and documents from a document library.
View Items  -  View items in lists and documents in document libraries.
Open Items  -  View the source of documents with server-side file handlers.
View Versions  -  View past versions of a list item or document.
Delete Versions  -  Delete past versions of a list item or document.
Create Alerts  -  Create alerts.
View Application Pages  -  View forms, views, and application pages. Enumerate lists.
Browse Directories  -  Enumerate files and folders in a Web site using SharePoint Designer and Web DAV interfaces.
View Pages  -  View pages in a Web site.
Enumerate Permissions  -  Enumerate permissions on the Web site, list, folder, document, or list item.
Browse User Information  -  View information about users of the Web site.
Use Remote Interfaces  -  Use SOAP, Web DAV, the Client Object Model or SharePoint Designer interfaces to access the Web site.
Use Client Integration Features  -  Use features which launch client applications. Without this permission, users will have to work on documents locally and upload their changes.
Open  -  Allows users to open a Web site, list, or folder in order to access items inside that container.
Edit Personal User Information  -  Allows a user to change his or her own user information, such as adding a picture.
Manage Personal Views  -  Create, change, and delete personal views of lists.
Add/Remove Personal Web Parts  -  Add or remove personal Web Parts on a Web Part Page.
Update Personal Web Parts  -  Update Web Parts to display personalized information.


These permission takes even from the root site, which is not being used.
Someone knows where these problems can come, I can not look. Preproduction is configured the same way and do not have such failures.
Could anyone help me with this?