If you have mate installed including the f28-backgrounds-base and f28-backgrounds-mate packages... and you try to remove f27-backgrounds-base and f27-backgrounds-mate... it wants to take mate-desktop and mate-system-monitor with it. Obviously the f28 build of mate depends on the f27 backgrounds. Can the f27-background dependencies be dropped please?
mate-settings-daemon-1.20.1-2.fc28 mate-desktop-1.20.1-4.fc28 has been submitted as an update to Fedora 28. https://bodhi.fedoraproject.org/updates/FEDORA-2018-b382ad17b5
Done!
mate-desktop-1.20.1-4.fc28, mate-settings-daemon-1.20.1-2.fc28 has been pushed to the Fedora 28 testing repository. If problems still persist, please make note of it in this bug report. See https://fedoraproject.org/wiki/QA:Updates_Testing for instructions on how to install test updates. You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2018-b382ad17b5
mate-desktop-1.20.1-4.fc28, mate-settings-daemon-1.20.1-2.fc28 has been pushed to the Fedora 28 stable repository. If problems still persist, please make note of it in this bug report.