Comment 11 for bug 1749007

You maybe tried before the package was actually built?

You can also try by downloading the debs on https://launchpad.net/ubuntu/+source/libgtop2/2.38.0-2ubuntu0.18.04.1/+build/14822012

$ wget https://launchpad.net/ubuntu/+source/libgtop2/2.38.0-2ubuntu0.18.04.1/+build/14822012/+files/libgtop2-common_2.38.0-2ubuntu0.18.04.1_all.deb https://launchpad.net/ubuntu/+source/libgtop2/2.38.0-2ubuntu0.18.04.1/+build/14822012/+files/libgtop-2.0-11_2.38.0-2ubuntu0.18.04.1_amd64.deb
$ sudo dpkg -i *.deb
$ gnome-system-monitor

but that's testing the deb version of gnome-system-monitor, the snap is going to be rebuilt to use the change...