The problem is with the STIX fonts on your system. STIX comes in several forms. The original form was a set of 29 fonts with names like
STIXSizeOneSym, each in its own font family. Recently, they were repackaged into a set of 5 fonts in families
STIXMath that are designed to work with Microsoft Word. Unfortunately, this repackaging makes them unusable by MathJax (many of the important characters are no longer accessible from within a web browser).
Normally, MathJax will ignore the repackaged fonts and use its web fonts instead. But it appears that Fedora installations now ship with the STIX Word fonts, but have aliased the original font names to point to the new STIX Word fonts. This is an error, in my opinion, as they are not interchangeable. For example, the
STIXSizeOneSym font had larger versions of the integrals, sums, parentheses, etc, at their usual unicode positions, but STIX Word has normal sized characters at those locations, and the larger sizes are inaccessible to the browser.
What you are seeing is the result of that font aliasing. Your Linux is telling MathJax that it has the original STIX fonts, but really all it has is the STIX Word fonts. MathJax goes ahead and uses the fonts that it is told are available, but the characters are not correct, so the results are not what they should be.
There are several possible solutions:
Disable the STIX fonts on your system. This way MathJax won't find them, and will use its web fonts as usual.
Remove the alias for
STIXSizeOneSym, which is the font that MathJax uses to determine if the STIX fonts are available. If that one is not found, MathJax will not use local STIX fonts.
Install local copies of the MathJax fonts; these are used in preference to local STIX fonts. There may be a package for MathJax fonts for your Linux already, so that would make it easy to install them. If not, you can download them directly from the MathJax GitHub repository. Note that you will have to download them each individually (you may have to use the "Raw" button at the upper right after clicking on a font name), and install the complete set (I think there are 26).
There is a "hidden" menu that you could use to select the font to be used. Use your browser's console window to type
This will add a
Font Preferences menu to the
Math Settings submenu of the MathJax contextual menu (right click on any equation to get the menu). The font menu lets you select any of MathJax' font options. Select
TeX (web). Note that this will cause the page to reload. The menu will no longer be available, so if you want to change back, you will need to give the command above again.
I hope one of those does the trick for you.