Incorrect default formatting for \mciteSubRef{}

[tscmacdonald]

I'm writing a manuscript in Overleaf, generated from the default achemso template and making use of group citations through mciteplus. When re-citing subentries of a grouped citation, by default the citation is no longer superscript and a full stop appears between the number and letter:

I believe that the correct formatting is superscript with no full stop. This can be corrected with \renewcommand{\mcitesubrefform}{\textsuperscript{\arabic{mcitebibitemcount}\alph{mcitesubitemcount}}}, which renders like this:

[josephwright]

Could you add a full example of your input?

[tscmacdonald]

MWE:

\documentclass[journal=jacsat]{achemso}
%\renewcommand{\mcitesubrefform}{\textsuperscript{\arabic{mcitebibitemcount}\alph{mcitesubitemcount}}}
\title{An \textsf{achemso} demo}
\begin{document}
\section{Introduction}
I like to cite in groups.\cite{Merrifield1968,*Merrifield1971} Sometimes I like to cite the subentries too, like this\mciteSubRef{Merrifield1968} or this.\mciteSubRef{Merrifield1971}
\bibliography{bibliography}
\end{document}

With the \renewcommand switch commented out, as above, it renders like this:

While this (with the \renewcommand uncommented) is my expected appearance:

As an aside: \mciteSubRef can only take one argument and doesn't compress cited subentries. There is a useful code snippet on StackExchange that allows subentry citation in a more natural way (which I use in my own documents) that you may wish to consider for improved functionality here, but I'm not sure if it's compatible with natbib.