Created attachment 1474035 [details] VDC showing correctly.
Closing as WORKSFORME, as Perry and I talked on IRC and neither of us can reproduce this anymore.
Created redmine issue https://projects.theforeman.org/issues/24681 from this bug
Also appears to affect 6.3. The cause is: for bug 1564087, we set the global connection overall connection TTL for connections in HornetQ/Artemis to 24 hours. However, in HornetQ 2.4.7 (in 6.3) and Artemis (Candlepin master), the "invm" connection type that we use does not use a connection ttl by default, and does not behave well when it is set globally.
snap 23, not 63
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHSA-2018:2927