My expectation would be that:
-when the "Consider only stable builds" checkbox is checked, Cobertura
publishing would be skipped if the build had any status other than SUCCESS
-when the "Consider only stable builds" checkbox is not checked, Cobertura
publishing would be skipped if the build had any status other than SUCCESS or
UNSTABLE
-if the build was UNSTABLE when the Cobertura publisher was running, if there
was a problem in the publishing, it would result in the build result being set
to FAILURE

What I'm currently seeing is that UNSTABLE builds are always skipped entirely,
regardless of the setting of the "Consider only stable builds" checkbox.

I'm planning on posting a candidate patch to address this defect shortly.