Runtime Error Could not find resource for relative : /consumers//entitlements [...]

I had a few hosts/jobs frozen under Katello 3.0-rc3. After forcing the jobs
to unlock, and performing an upgrade to rc4, I'm getting the following
errors for two test hosts which were previously stuck (hosts which had not
previously attempted registration work fine):

Runtime Error Could not find resource for relative :
/consumers//entitlements of full path:
https://localhost:8443/candlepin/consumers//entitlements

I'm not able to subscribe, remove the hosts from within the foreman UI, or
delete the hosts. I'm guessing there's some leftover entry in a db
somewhere, but I'm not sure where to check, and how to remove this. Can
someone point me in the right direction?

Thanks.

-salman