[SOLVED] - "Bold" doesn't work with Firefox

[SOLVED] - "Bold" doesn't work with Firefox

UPDATE (Nov 3, 2021):
This issue was Firefox related and is solved with Firefox version 94.0.

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This is a new issue and it only occurs with the web client with Firefox 93.0 on macOS Monterey 12.0.1, affecting everything that should be bold, including headlines, note labels etc.
All other formatting options for text are working.
I have not seen this with other browsers and on Windows, it seems to be a issue exclusively related to Firefox/macOS Monterey.

First screenshot is Firefox, second one is Chrome: