Courier font bullet point on a page in an attached document leads to that page's preview showing up as blank/empty

Issue Summary

On a Confluence page, attach a word document where the document's content has a bullet point in the Courier font (default Microsoft Office empty-circle bullet).
In the resulting preview, the page containing the Courier font bullet point will appear to be blank.
Clicking on an empty space on the seemingly blank page preview, and then dragging down (to mimic text being highlighted) will reveal that text does exist, but is completely transparent, and therefore unreadable.

Steps to Reproduce

Attach the sample doc (Sample.docx) to a Confluence page, and click on it to generate the document preview.

Expected Results

Each of the 4 pages should have a visible/readable preview.

Actual Results

The preview for the page which contains the Courier font bullet point will appear blank, but it does have the original text that's completely transparent/invisible (see attached issue_screenshot.png).

Workaround

Highlight the bullet in the source document, change the font from Courier to Windings, or use a different fixed width font like Consolas, and attach the modified document in place of the original to re-generate a fully-visible preview.

Note: the issue may also appear in the previews for PDF files containing the Courier font/bullet; the workaround of changing the font in the PDF to a different fixed width font still applies.