This issue was detected in OpenOffice 3.2 and 3.2.1 on Windows XP.
Here is the process to reproduce the issue:
1. Add an image to the document through the menus: Insert > Picture > From File...
2. Right-click on the image and select Description from the context menu.
3. Fill in the fields Title and Description.
4. Quit the Description dialog by pressing OK.
5. Right-click on the image and select Caption from the context menu.
6. Fill in the Caption field; quit the caption dialog by pressing OK.
7. Right-click on the image (i.e. on the image inside the frame created by the
caption, as opposed to a right-click on the frame itself), and select
Description from the context menu.
8. The fields Title and Description (filled in at step 3) are now empty.

Current workaround: add the caption first, and then the Title and Description.
Few people will be aware of the disappearing Title and Decription and think of
the workaround.
The title and description are needed for blind users (or any screen reader
users) and for exporting to audio books (e.g. in the DAISY format, with the OOo
extension odt2daisy). In other words, it's an accessibility issue.