PDF export garbles auto-skewed or auto-bolded fonts

[despens]

This issue is unique.

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Operating System

other (specify in description)

Version information

9.0.3.29

Expected Behavior

Some typefaces do not provide all possible style combinations as separate versions or via parameters. The following example shows a font that has regular, bold, and italic versions, but no bold-italic version, in the editor:

Actual Behavior

You can see that the bold-italic version is rendered by skewing the bold version.

This is usable in the editor. However, when exporting to PDF, the missing font is substituted by a skewed version, but with garbled symbols:

This is happening on Linux and macOS, with the desktop editor and a self-hosted web editor, same version numbers of the editor.

Reproduction Steps

1. Choose a font that doesn't have all variants available. (You can also temporarily uninstall one variant from your system.)
2. Use the missing variant in the editor.
3. Export to PDF.

Additional information

This is happening on Linux and macOS, with the desktop editor and a self-hosted web editor, same version numbers of the editor.