Some users who generate a support bundle via the UI run into issues where the content of the bundle get corrupt. Unfortunately there is not much logging in the logs to determine what could have potentially caused this issue. The support bundle contents usually stop after the browser.md is generated. Doing a quick test locally, the about.md content is next to be generated:

Writing file: nodes/slave/test/logs/all_2016-03-11_05.59.17.log to the support bundle.
Writing file: nodes/slave/test/logs/all_2016-03-11_06.02.04.log to the support bundle.
Writing file: browser.md to the support bundle.
Writing file: about.md to the support bundle.

however the about.md content is never generated.