I noticed, when included the plotly library in my HTML header, MathJax stopped working. All my LaTeX formulas appeared in raw source form instead of formatted math formulas.
I managed to fix it by including Plotly first.
That is, it works in this order:
…but if Plotly is loaded after MathJax, MathJax stops working.
I have no idea why, but I’m glad I found a workaround. I hope this helps others.