UI not responding when only external monitor is active

Ubuntu 22.10
nvidia-driver-525

With the recent nvidia drivers (two or three releases), if I switch ON the external monitor (HDMI) and OFF the laptop one, the UI (Gnome) responds very late to input, causing a seconds delay between click and actions. If I turn on the laptop monitor, it responds as expected.

I've tried open source drivers but the notebook doesn't reach the login screen.

Thanks,
Roberto

ProblemType: Bug
DistroRelease: Ubuntu 22.10
Package: nvidia-driver-525 525.78.01-0ubuntu0.22.10.1
ProcVersionSignature: Ubuntu 5.19.0-31.32-generic 5.19.17
Uname: Linux 5.19.0-31-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.23.1-0ubuntu3
Architecture: amd64
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Mon Feb 13 08:03:59 2023
InstallationDate: Installed on 2022-10-24 (111 days ago)
InstallationMedia: Ubuntu 22.10 "Kinetic Kudu" - Release amd64 (20221020)
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=it_IT.UTF-8
 SHELL=/bin/bash
SourcePackage: nvidia-graphics-drivers-525
UpgradeStatus: No upgrade log present (probably fresh install)