The most likely access control causing the lack of access is role-based access control (RBAC). In RBAC, access to resources is determined by the roles assigned to users. Since the engineer's account was not moved to the new group's role, the engineer does not have the necessary permissions to access the new team's shared folders.
Role-based access control (RBAC): Assigns permissions based on the user's role within the organization. If the engineer's role does not include the new group's permissions, access will be denied.
Discretionary access control (DAC): Access is based on the discretion of the data owner, but it is not typically related to group membership changes.
Time of day: Restricts access based on the time but does not affect group memberships.
Least privilege: Ensures users have the minimum necessary permissions, but the issue here is about group membership, not the principle of least privilege.