I am the engineer responsible for, depending on your experience, the enhancement of how math equations are displayed in canvas or the string of horrific errors that rendered math quizzes unreadable. If you're in the latter camp, I am truly sorry. This turned out to have complexities I did not envision. I owe you a beer or a coffee.
While investigating why math is sometimes garbled I stumbled on a surprising pattern for how users are creating equations in their content and wanted to say a couple things about how to make it better.
In a number of places an equation will be all in plain text except for one symbol, say ≤, which was injected using the rich content editor's equation editor. This creates something like:
When this is saved then viewed Canvas will have MathJax typeset the math, which in this case is just the ≤, leaving the rest of the equation untouched. This has a couple effects. First, the symbol is rendered in a different font than the surrounding text. Not a big deal, but not ideal. More importantly this does not provide the assistive support MathJax provides to your students who use a screen reader or a screen magnifier. It's also more effort than just creating the whole equation as a single entity. I suggest you use the equation editor to create the entire equation. This provides the best user experience.
If you prefer not to use the equation editor, then I suggest that you use the unicode character for the symbol you need. Google "unicode less than or equal to symbol" and the top result should show the character you can copy and paste. Screen readers generally know what these characters are and will read then appropriately. (Unicode characters are characters just like 'a' or 'z', but can display fancy glyphs like emojis and mathematical symbols.)
Next, if you discover your equations are not displaying correctly, edit the content and look at the HTML (click the </> button in the bottom right corner of the Rich Content Editor). If you see anything that looks like it was generated by MathJax, HTML that looks like
then something has gone wrong and MathJax generated output was saved as part of your content, which should never have happened. While this shouldn't happen again, you are looking at corrupt content that's already saved in our database. We have a tool that Canvas support can use to try and repair your content, but it only works some of the time. Your best bet is to recreate the content. I know that's not an ideal answer, but it will provide the best experience for your students and save you headaches in the future if you reuse the content later on.
I hope this has been helpful, and now that we have the bugs worked out (fingers crossed) you should be pleased to know that your students using assistive technology have better access to math equations in Canvas than before.
I'm an Instructure Senior Software Engineer, even though I'm educated as a Mechanical Engineer, a vocation I practiced exactly once, getting an engine rebuilt in exchange for calculating wheel rates for the springs on a stable of race cars. I'm a drummer, a father of 2 adult daughters, and a fan of hockey in the winter and baseball in the summer.