Most of our jobs have "Discard old builds" enabled.

We just noticed that if you look at the job configuration, "Discard old builds" is not set (ticked). However, if you look at the actual config.xml file, the setting is definitely there.

This problem was noticed in Jenkins 1.637. When we reverted back to our previous version, 1.634, then the "Discard old builds" setting reappeared when you look at the job configuration.

I don't know whether this is only a UI problem, or whether the discard action itself is also suppressed.

Looking at the change log between 1.634 and 1.637, the only change that looks related is pull 1888.