When I look at dmesg it appears that screen lock is causing a segfault:
[ 595.735328] Lockdown: systemd-logind: hibernation is restricted; see man kernel_lockdown.7
[ 597.651594] gnome-shell[7692]: segfault at 1195 ip 00007f94d6bcee41 sp 00007fffe593b4f8 error 4 in libc-2.31.so[7f94d6a6d000+178000]
[ 597.651601] Code: 01 0f 84 e2 03 00 00 0f 82 cc 03 00 00 49 89 d3 89 f8 31 d2 c5 c5 ef ff 09 f0 25 ff 0f 00 00 3d 80 0f 00 00 0f 8f ef 03 00 00 <c5> fe 6f 0f c5 f5 74 06 c5 fd da c1 c5 fd 74 c7 c5 fd d7 c8 85 c9
[ 599.073507] Lockdown: systemd-logind: hibernation is restricted; see man kernel_lockdown.7
ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: gnome-screensaver (not installed)
ProcVersionSignature: Ubuntu 5.4.0-31.35-generic 5.4.34
Uname: Linux 5.4.0-31-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair nvidia_modeset nvidia
ApportVersion: 2.20.11-0ubuntu27
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: ubuntu:GNOME
Date: Tue May 26 19:45:14 2020
InstallationDate: Installed on 2019-11-25 (183 days ago)
InstallationMedia: Ubuntu 19.10 "Eoan Ermine" - Release amd64 (20191017)
SourcePackage: gnome-screensaver
UpgradeStatus: No upgrade log present (probably fresh install)
---
ProblemType: Bug
ApportVersion: 2.20.11-0ubuntu27
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: ubuntu:GNOME
DistroRelease: Ubuntu 20.04
GnomeSessionIdleInhibited: No
GnomeSessionInhibitors: None
GsettingsGnomeSession:
org.gnome.desktop.session session-name 'ubuntu'
org.gnome.desktop.session idle-delay uint32 0
InstallationDate: Installed on 2019-11-25 (184 days ago)
InstallationMedia: Ubuntu 19.10 "Eoan Ermine" - Release amd64 (20191017)
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair nvidia_modeset nvidia
Package: gnome-screensaver 3.6.1-11ubuntu4
PackageArchitecture: amd64
ProcVersionSignature: Ubuntu 5.4.0-33.37-generic 5.4.34
Tags: focal
Uname: Linux 5.4.0-33-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip docker lpadmin lxd plugdev sambashare sudo
_MarkForUpload: True
apport information