Para el MWE que se indica a continuación:
\documentclass[english]{article}
\usepackage[style=authoryear,maxcitenames=2]{biblatex}
\usepackage{filecontents}
\begin{filecontents}{sample.bib}
@Article{Erkus2019,
author = {Erkus, A. and Second, B. and Third, C.},
title = {This is a paper},
journal = {Journal of Engineering},
year = {2019}}
@Article{Erkus2018,
author = {Erkus, A. and Third, B.},
title = {This is another paper},
journal = {Journal of Another Engineering},
year = {2018}}
\end{filecontents}
\addbibresource{sample.bib}
\begin{document}
\cite{Erkus2019}
\cite{Erkus2018}
\printbibliography
\end{document}
Recibo las citas como
Erkus, segundo, et al. 2019
Erkus y Tercera 2018
La primera cita debe ser
Erkus, et al. 2019
No entiendo por qué BibLaTeX considera que aquí hay desambigüedad.