Your package erlang-riak_core failed to build from source in current F28. https://koji.fedoraproject.org/koji/taskinfo?taskID=24784268 For details on mass rebuild see https://fedoraproject.org/wiki/Fedora_28_Mass_Rebuild
erlang-cowlib-2.2.0-2.fc28 erlang-eleveldb-2.0.34-7.fc28 erlang-gproc-0.7.0-3.fc28 erlang-hyper-0-0.4.20161011git4b1abc4.fc28 erlang-meck-0.8.8-4.fc28 erlang-riak_core-2.1.10-3.fc28 erlang-riak_ensemble-2.1.8-5.fc28 erlang-rpm-macros-0.2.9-1.fc28 erlang-snappy-1.1.1-0.11.git348da43.fc28 erlang-stdlib2-0-0.3.20170810git5ccd9b2.fc28 has been submitted as an update to Fedora 28. https://bodhi.fedoraproject.org/updates/FEDORA-2018-f305d46bc7
couchdb-1.7.1-8.fc28, erlang-cowlib-2.2.0-2.fc28, erlang-eleveldb-2.0.34-7.fc28, erlang-eper-0.97.3-6.fc28, erlang-gproc-0.7.0-3.fc28, erlang-hyper-0-0.4.20161011git4b1abc4.fc28, erlang-meck-0.8.8-4.fc28, erlang-riak_core-2.1.10-3.fc28, erlang-riak_ensemble-2.1.8-5.fc28, erlang-rpm-macros-0.2.9-1.fc28, erlang-snappy-1.1.1-0.11.git348da43.fc28, erlang-stdlib2-0-0.3.20170810git5ccd9b2.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-f305d46bc7
couchdb-1.7.1-8.fc28, erlang-cowlib-2.2.0-2.fc28, erlang-eleveldb-2.0.34-7.fc28, erlang-eper-0.97.3-6.fc28, erlang-gproc-0.7.0-3.fc28, erlang-hyper-0-0.4.20161011git4b1abc4.fc28, erlang-meck-0.8.8-4.fc28, erlang-riak_core-2.1.10-3.fc28, erlang-riak_ensemble-2.1.8-5.fc28, erlang-rpm-macros-0.2.9-1.fc28, erlang-snappy-1.1.1-0.11.git348da43.fc28, erlang-stdlib2-0-0.3.20170810git5ccd9b2.fc28 has been pushed to the Fedora 28 stable repository. If problems still persist, please make note of it in this bug report.