Selecting area to grab puts gnome-screenshot into a 100% CPU busy loop

Save dialog never appears.

I have used gnome-screenshot many times daily for years.
This started happening yesterday.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: gnome-screenshot 3.36.0-1ubuntu1
ProcVersionSignature: Ubuntu 5.4.0-58.64-generic 5.4.73
Uname: Linux 5.4.0-58-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.20.11-0ubuntu27.14
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: ubuntu:GNOME
Date: Tue Dec 15 15:05:15 2020
InstallationDate: Installed on 2018-05-05 (955 days ago)
InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Release amd64 (20180426)
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: gnome-screenshot
UpgradeStatus: Upgraded to focal on 2020-07-27 (141 days ago)