Summary

Strikethrough is shown as underline or overline in exported PDF with custom PDF Export Language TTF/TTC installed

Steps to Reproduce

1. Navigate to Confluence administration > PDF Export Language Support
2. Install Japanese font (c.f. IPA font (any of Ver.004.01))
3. Create a page which contains strikethrough
   
4. Export a Confluence page as PDF

Expected Results

The strikethrough is shown as is in the original page or in exported PDF with the default font (Helvetica).

Actual Results

Strikethrough is not in the middle and drifted above the text

Workaround

Download and install an alternative TTF file like below:
https://github.com/minoryorg/Noto-Sans-CJK-JP/blob/master/fonts/NotoSansCJKjp-Regular.ttf