I have noticed that capital Sigma, both as $\Sigma$, and as the summation symbol as in $\sum_{i}^{n}$, appears to have been subject to a recent graphics change. The $\sum$ symbol now looks markedly different from what it used to look like a few days ago. Here is a comparison between MathJax and native LaTeX: $$\sum_{i=0}^{\infty} i^2$$$\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\;\:\:$

Just in case that this is actually a fault with my system, here's a screenshot of what $$\sum_{i=0}^{\infty} i^2$$ currently looks to me on M.SE:

What's going on here? Why this change? I know that it is inconsequential to the mathematics concerned, but I think that it is aesthetically inferior.

EDIT: the below is due to me recently installing the STIX fonts, which came with an installation of texlive-full. This question is now concerned with how to avoid rendering the aesthetically inferior fonts.

I have noticed that capital Sigma, both as $\Sigma$, and as the summation symbol as in $\sum_{i}^{n}$, appears to have been subject to a recent graphics change. The $\sum$ symbol now looks markedly different from what it used to look like a few days ago. Here is a comparison between MathJax and native LaTeX: $$\sum_{i=0}^{\infty} i^2$$$\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\;\:\:$

Just in case that this is actually a fault with my system, here's a screenshot of what $$\sum_{i=0}^{\infty} i^2$$ currently looks to me on M.SE:

What's going on here? Why this change? I know that it is inconsequential to the mathematics concerned, but I think that it is aesthetically inferior.