Yes; where do I send it?

I am getting the same error with Chrome and Safari on MacOS.

For completeness the answer for my problem was to add:

<meta charset = "UTF-8"> to the head of the calling page. Thanks Christian!

By the way Michael Beeson's example renders perfectly for me on bibbase.org, including alpha, beta, pi and French accents.

I am having similar problems with MathJax rendering. See https://markcwilson.site/Research/Outputs/papers.html

which embeds the result of processing my bibfile via bibbase.org. The output looks great on bibbase.org but not when embedded (e.g. abstract for 3rd paper in 2019). I have tried using the MathJax-related code from the source of the version on  bibbase.org, but no luck.