This bug is related to JRA-36670 which regards losing content while hitting the escape button. The resolution of JRA-36670 is a bit controversial, it has a resolution won't fix and explanation that it is "by design". However people report that they lose content while accidentally pressing the escape button.

This bug regards editing a description of an issue, and clicking File->Save Page As, or pressing the keyboard shortcut ctrl-s. The dialog for choosing a file name appears. When clicking the cancel button a user returns to editing an issue, but while hitting the escape button instead, the dialog closes which is correct behavior, but simultaneously all updates to description are lost.
I think the escape button should have the action "close the dialog" and nothing else.

I have the habit of pressing ctrl-s, and after that pressing the escape button. Due to this I lose content very often.