Are you sure this isn't an environmental issue? The changes committed to rebase were minimal and should not have caused this problem. Additionally, looking at the build information in koji shows that the tomcat-lib package does in fact provide "tomcat-lib = 1:8.0.53-1.fc27". I'll setup a VM to test as soon as I can, but I don't see any cause for this at first glance.
I was under the impression that adding a new build would remove the old one, but maybe that isn't the case. I do see that this update is pending the push to testing, so maybe when that happens the old build will be removed. I'm going to wait and see what happens when this update is pushed to testing. If it doesn't resolve it, I'll try untagging the 8.0.37-3 build.