APM start two session for Office App

Hi,
after integrating F5 with Azure Active Directory (Azure AD) for Sharepoint authentication, I noticed that all content is opened correctly; Word, Wxcel, Powerpoint files are opened correctly in online mode, but the only thing that cannot be made to work is to open a file with the relative application.

What I notice is that two separate sessions are started:

it is as if the MRHSession cookie was not considered as the GET call is not performed by the Client/Vs/Pool, but directly by the application.
In fact, from the log I notice that the name of the app is inserted in the header:

I tried to insert the clientless mode inside an iRule, but the result doesn't change.

Some idea?

Thanks

/MM