When reviewing my question, I realized that the body changes three times during the loading of the page (the screenshots below were taken as the page was loading, at various stages - there is a ~1 second delay between each of the formatting)
- First the unformatted version is displayed
- It then proceeds asynchronously to a first formatting (codename: NICE) to provide a nice visualization of the code
- Finally, a new version of the formatted equation is displayed (codename: UGLY), where a boldface font replaces the previous one
The final font reminds me of Computer Modern but I am not sure.
Why does the ugly font replaces the nice one? (nice = similar to the other font, or at least which does not jump to the reader face)
Is this because of typesetting rules which cannot be enforced with the nice font?