Just came here to report that I've experienced the same issue on Windows Server 2025 Standard with XCP-ng Windows Guest Tools 9.1.146.0 installed.
Restarting the service "Xen Guest Agent (Rust-based)" works, but after a reboot of the VM the IP is not visible anymore in XO or XCP-ng Center.
When disconnecting the vNIC and connecting it again, the IP adress is displayed for a couple of seconds, but disappears af
I "fixed" it by setting the startup type of "Xen Guest Agent (Rust-based)" to "Automatic (Delayed start)"
No problems with Debian 12 or AlmaLinux 9.