LaTeX Error: begin{tcolorbox} on input line x ended by end{myenv} when using new environment

Defining a new environment with a tcolorbox with some options strangely leads to a compilation failure that disappears if I remove [hbox]

documentclass{article}

usepackage{tcolorbox}

newenvironment{myenv}
{begin{tcolorbox}[hbox]}
  {end{tcolorbox}}

begin{document}

begin{myenv}
  blah
end{myenv}

end{document}

I can’t define tcbset{capture=hbox} because it’s the only option that’s protected from tcbset

documentclass{article}

usepackage{tcolorbox}

newenvironment{myenv}
{tcolorbox[hbox]}
  {endtcolorbox}

begin{document}

begin{myenv}
  blah
end{myenv}

end{document}