I have a matrix job with two axis, one is our platform name, the other is the postgres version (which only has one entry and which we use to make sure the builds happen on machines that have postgres installed).

We've been having sporadic failures in this job (that's not a bug in jenkins ) but when I went to look at two failed builds this morning, I got nothing underneath the "Console Output" heading on the:

/job/<job-name>/environment=<x>,label=pg848/201

The build artifacts were also missing.

Clicking around different builds, I found this to be the case on all builds.
The blue balls showed in:

/job/<job-name>/201/

...but clicking on any of them gave the result I described above.

I went off to google, found some similar issues but they all seemed old.
I went to nose around the file system of the master.

The really alarming this is that:

jenkins@<host>:~/jobs/<job-name>/configurations/axis-environment

...didn't have subfolders for all the environment axis options, and those it did have were missing contents for the subfolders for the label axis:

jenkins@<host>:~/jobs/<job-name>/configurations/axis-environment/<x>/axis-label> ls

...gave nothing.

I had a bit more of a google, and by now the job had kicked off again this morning.

I returned to the web ui. Now, going to:

/job/<job-name>/environment=<x>,label=pg848/201

...gives grey balls for each of the environenments and if I go to:

/job/<job-name>/environment=<x>,label=pg848/201

...I now get a 404, whereas before I got the empty configuration page.

This is pretty scary.