Some build jobs regularly loose all their build artifacts.
Then everything becomes as if these jobs have never been run before.
This make depending projects (using copy-artifacts) fail.

Such jobs have "Discard old builds" and "Max # of builds to keep" set.
This occurs only for a few weeks, so this may be a regression.
Currently affected version is 1.492

There is no obvious raison in which situation the artifacts get deleted.
This can occur even if the be job is not run (e.g. nothing been committed)
This began to occur shortly (but not immediately) after I started creating multi-configuration jobs.
This can affect both multi-configuration and/or freestyle projects.