It is expected as the OOB update for 24/25H2. Code: OOB for Windows 11 v25H2/24H2: KB5070773 (26x00.6901)
Wait, how does an offline upgrade install work? I was under the impression that upgrade installs can only be performed online. Either I missed something in the last few years, or I misunderstood your message. I wouldn't be surprised if it's the latter, apologies if so.
We are talking about ISO upgrades, so disconnecting the (w)lan connection means offline. When you are upgrading by Windows Update. This is basic stuff.