The supported mono arches for EPEL7 has been updated and it now supports more arches than before. Because of that, not only can this package not be installed on the new arches, it is blocking the building of other packages that depend on it. Please rebuild this package so that it can be installed on all RHEL 7.6 arhces. If you have not responded in a week, we will have a proven packager rebuild it. If you know you will not be able to get to it and would like it fixed sooner, please let us know in this bug.
gnome-sharp-2.24.2-13.el7 has been submitted as an update to Fedora EPEL 7. https://bodhi.fedoraproject.org/updates/FEDORA-EPEL-2018-c00dbfbbf9
gnome-sharp-2.24.2-13.el7 has been pushed to the Fedora EPEL 7 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-EPEL-2018-c00dbfbbf9
gnome-sharp-2.24.2-13.el7 has been pushed to the Fedora EPEL 7 stable repository. If problems still persist, please make note of it in this bug report.