Session lost reference to the client

After user authenticated and created a session, after token expired and client use the refresh token, user receive this message:

{
    "error": "invalid_grant",
    "error_description": "Session doesn't have required client"
}

Looking at the user session tb, I can see this:

There’s two session that have no client.

What can cause this?

Keycloak: 15.1.1

Thank you