As @johannesbottcher suggests: Setting the page number to zero, the page style to empty but setting the visual output of the page number to i is a bit strange. A package like hyperref wont pick that up.
\begin{titlepage}\maketitle\end{titlepage} is wrong. It should just be \maketitle.
https://github.com/kks32/phd-thesis-template/blob/master/Classes/PhDThesisPSnPDF.cls#L933
As @johannesbottcher suggests: Setting the page number to zero, the page style to empty but setting the visual output of the page number to i is a bit strange. A package like hyperref wont pick that up.
\begin{titlepage}\maketitle\end{titlepage}is wrong. It should just be\maketitle.