You installed insider preview updates, they now are in the pre 25H2 stage, the real 25H2 public release is expected in september/october.
He applied the Insider Preview 25H2 EP on ltsc and that worked, as already was tested when it was first released. It is a fake upgrade, if it works for real on LTSC, not a new major release, just by EP like from 1903>1909, 19041 > 19045, and so on...
[DISCUSSION] Hotpatching for Windows Server 2025 (and Windows 11 24H2 - no subscriptions needed!) Hotpatches are meant for servers or enterprise environments who can't reboot as much as simple desktop pc's.