Acro in compatibility mode freezes when using plural forms (e.g. \acp) of undefined acronyms

[ytzemih]

An MWE that shows the behaviour under pdflatex and luatex (in my case, Version 3.141592653-2.6-1.40.24 (TeX Live 2022/Debian)) is given here:

\documentclass{article}
\usepackage{acro}[=v2] % <== happens only in compatibility mode
% \DeclareAcronym{MWE}{short = MWE, long = Minimum Working Example}
\begin{document}
\Aclp{MWE} % <== comment to avoid [pdf|lua]latex freeze 
% \aclp{MWE} 
% \Acp{MWE} 
% \acp{MWE} 
\acs{MWE} % <== throws an error as expected if MWE is undefined
\ac{MWE}
\end{document}

The "p"-commands seem to be affected consistently after a few tests. It seems as if there is problem with plural-form compatibility?

Because of known efficiency problems, I need to continue to use the compatibility mode, the latter of which is totally fine for my purposes. But the freezes are happening quite likely when switching between many (larger) documents and acronym lists.

Thanks for a quick check.