Problem compiling \binom with breqn

I can latex the file foo.tex just fine when I use amsmath, but it gives the error message below when breqn is loaded instead.

\ProvidesExplPackage{breqn}{2020/02/16}{0.98h}{Breaking equations}

If that matters. I run on Ubuntu 20.04 with texlive. I see no problem with texlive on Debian 10.

\documentclass{article}
%\usepackage{amsmath}
\usepackage{breqn}
\begin{document}
a $\binom{x}{y}$ b
\end{document}

The latex output is this:

>latex foo.tex
This is pdfTeX, Version 3.14159265-2.6-1.40.20 (TeX Live 2019/Debian) (preloaded format=latex)
 restricted \write18 enabled.
entering extended mode
(./foo.tex
LaTeX2e <2020-02-02> patch level 2
L3 programming layer <2020-02-14>
(/usr/share/texlive/texmf-dist/tex/latex/base/article.cls
Document Class: article 2019/12/20 v1.4l Standard LaTeX document class
(/usr/share/texlive/texmf-dist/tex/latex/base/size10.clo)) (./breqn.sty
(/usr/share/texlive/texmf-dist/tex/latex/l3kernel/expl3.sty
(/usr/share/texlive/texmf-dist/tex/latex/l3backend/l3backend-dvips.def))
(/usr/share/texlive/texmf-dist/tex/latex/breqn/flexisym.sty
(/usr/share/texlive/texmf-dist/tex/latex/breqn/cmbase.sym)
(/usr/share/texlive/texmf-dist/tex/latex/breqn/mathstyle.sty))
(/usr/share/texlive/texmf-dist/tex/latex/graphics/keyval.sty)
(/usr/share/texlive/texmf-dist/tex/latex/tools/calc.sty)
Runaway argument?
\romannumeral \ifx \protect \@typeset@protect \expandafter \expandafter \ETC.
! Paragraph ended before \@tempa was complete.
<to be read again> 
                   \par 
l.855   \par

? 
! Extra \endgroup.
l.856   \endgroup

? 
! Undefined control sequence.
l.857   \EQ@displayinfo

? 
! Too many }'s.
l.858 }

? 
) (./foo.aux)
! Missing number, treated as zero.
<to be read again> 
                   \relax 
l.5 a $\binom{x}{y}
                   $ b
? 
! Illegal unit of measure (pt inserted).
<to be read again> 
                   \relax 
l.5 a $\binom{x}{y}
                   $ b
? 
[1] (./foo.aux) )
Output written on foo.dvi (1 page, 396 bytes).
Transcript written on foo.log.

wspr / breqn

Problem compiling \binom with breqn #50