I'm primarily looking for advice how to troubleshoot this issue.

We have a Jenkins instance (latest version (core + ~150 plugins). Everything works fine except there is a job, cron-triggered daily. Sometimes the actual build of this job just "disappears": the build is not visible in the UI, the build directory on the disk has the "beginning" of the build log ending in the middle of the build, and build.xml with the build metadata is also completely missing. Jenkins log doesn't contain anything related.

How can I go on  investigating what causes this? Anything I could enable in logging to provide more information?