Description:
Libreoffice Writer and Libreoffice Calc immediately hang when you type "fi" using the Linux Biolinum G or the Linux Libertine G font in bold. I have not tested this very comprehensively because it's a bit tedious (you have to kill and restart Libreoffice after each test...), but you *can* type "ff" in bold using Linux Libertine, which creates a ligature. There might be other letter combinations that cause a crash, but the only one I have found is "fi" (which makes me think it's related to ligatures, but I don't actually know). This does not seem to happen on Linux (at least, I could not reproduce on an up-to-date Manjaro VM).

Addendum : I ran a few more tests, but I can't say I understand the problem better. If you type "fi" using another font (or not in bold, or in bold italics as all these work), and then select that word and switch to bold and one of the problematic fonts, Libreoffice immediately hangs. *However*, if you do the same with "fif" there are no issues (and you get the ligature between the f and the i, so maybe that is not the problem after all).

Steps to Reproduce:
1. Create a new document with the latest version of Writer on Windows 10.
2. Switch the font to Linux Libertine or Linux Biolinum, and switch to bold.
3. Type "fi".

Actual Results:
Program becomes non-responsive and has to be manually killed.

Expected Results:
Well, displaying "fi" on the screen would be nice...


Reproducible: Always


User Profile Reset: No



Additional Info:
Version: 6.4.3.2 (x64)
Build ID: 747b5d0ebf89f41c860ec2a39efd7cb15b54f2d8
CPU threads: 4; OS: Windows 10.0 Build 18363; UI render: default; VCL: win; 
Locale: en-US (fr_FR); UI-Language: en-US
Calc: threaded