I just reinstalled Windows and started adjusting the settings. I changed the Change system locale setting to Finland, after which the subtitles broke and now appear in bold. I changed the setting back, but the issue still persists.
I also changed the language and regional settings so that the time and date display correctly here in Finland. This is probably related to some kind of encoding issue. Before I reinstalled Windows, on my old system I never changed the system locale, and it was probably set to English or something similar by default. As you can see, the Finnish subtitles in the picture are bold.
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