dbcheck works with objects which are dead on one end or the other. But it does not find the case where both objects are alive, but one half of the pair of linked attributes is missing.
Created attachment 12988 [details] patch for 4.6
Created attachment 12990 [details] patch for 4.5
Pushed to autobuild-v4-{5,6}-test.
(In reply to Stefan Metzmacher from comment #3) Pushed to both branches. Closing out bug report. Thanks!