I can't reproduce the bug using that same recipe either. So now I think I may have made a mistake in exactly how the recipe is to be followed. However, I am fairly sure that there is some way to make emax crash using malformed tags using approximately the same procedure. As far as I know, emax at Google is stock.
>
> I cannot reproduce the crash, neither in Emacs 28.2 nor in what will
> soon be Emacs 29.1. Does this happen if you start with "emacs -Q" and
> then follow the recipe you posted?
>
I cannot reproduce that crash either, I tried Debian's Emacs 28.2, and
Emacs 28 and 29. By any chance, does Google Emacs include local patches?