KaTeX plus sign faded out in Chrome

[pandichef]

In this equation
\operatorname{E}\left[X^{2}\right]=\sum\limits_{i=1}^{N}p_{i}x_{i}^{2} =
p\lambda^2 + (1-p)\alpha^2

the plus sign appears faded out in Chrome Version 81.0.4044.129 (Official Build) (64-bit). I tested this out in a raw HTML file (using https://katex.org/docs/browser.html); the problem appears in hugo-theme-pure only.