While performing the custom PDF export for Page/s, breaks page titles with umlaut letters.

Issue Summary

While performing the custom PDF export for Page/s, breaks page titles with umlaut letters. Issue is reproducible on Latest LTS 7.19.4 and Latest release 8.1.0

This is reproducible on Data Center: yes

Steps to Reproduce

1. Setup the Confluence DC setup. ( sandbox as separate process)
2. Create a Page, with Page Title containing "umlaut" character and content also has "umlaut" character in the description.
3. Published the Page.
4. Go to Space Tool -> Custom PDF Export , PDF
5. Select Page/Pages (Not All pages under tree). then click Export
6. When you open downloaded the PDF export, it contains Garbled Character for "umlaut" letters.
7. Strange behavior is, Page which we have exported. its title also gets garble. Somehow it is updating Garbled Page title into DB.

Expected Results

PDF custom page export should export "umlaut" letter as expected. This works as expected in Confluence Server (after disabling Sandbox process).

Actual Results

Attaching the supporting exported PDF and Snippet.

1. Create a Page with title containing umlaut letters. For eg : Brüder

2. Custom PDF Export

3. Exported PDF

4. Original Page also become garbled.

Workaround

Disable Sandbox process, but it has other side effect of OOM due to other space export operation.