Your package has Obsoletes:...%{_isa} or some form of it. It never worked because obsoleting work by package names and not by provides. You need either to remove it or fix it.
This bug appears to have been reported against 'rawhide' during the Fedora 28 development cycle. Changing version to '28'.
libkcapi-1.0.3-8.fc27 has been submitted as an update to Fedora 27. https://bodhi.fedoraproject.org/updates/FEDORA-2018-0809d69e15
libkcapi-1.0.3-8.fc26 has been submitted as an update to Fedora 26. https://bodhi.fedoraproject.org/updates/FEDORA-2018-2c6827444a
libkcapi-1.0.3-8.fc27 has been pushed to the Fedora 27 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-2018-0809d69e15
libkcapi-1.0.3-8.fc26 has been pushed to the Fedora 26 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-2018-2c6827444a
libkcapi-1.0.3-8.fc27 has been pushed to the Fedora 27 stable repository. If problems still persist, please make note of it in this bug report.
libkcapi-1.0.3-8.fc26 has been pushed to the Fedora 26 stable repository. If problems still persist, please make note of it in this bug report.