Is it true that they stopped selling the Navigo semaine card at CDG airport and at Orly airport?From the île de France mobilité webpage it seems that they still sell it . Could you please tell me what is happening?

Yes, it appears that the manager of the CDG airport train stations has decided to stop selling Navigo Decouverte cards (needed for Navigo Week passes) due to the extra time it takes for customers to set up their passes versus just selling fares on Navigo Easy (disposable) cards.
 
This was not a decision from the parent organization Transilien, to stop selling Navigo Decouverte cards at CDG Airport, but rather, the local Transilien staff manager / administration at CDG Airport making this decision on their own.  This is why support staff at Transilien have no answer as to whether Navigo is sold or not sold at CDG nor why.  It's really frustrating.
 
So as of Sept 2025, your only option to use Navigo Week pass at CDG airport upon arrival is to install the IDF Mobilites app or Bonjour RATP and purchase the Navigo Week pass on your phone.  Keep in mind that only European mobile phone numbers can create an account for use on these apps. (An SMS will be sent to during account creation.)