Normal font in main body counters using classicthesis

I am writing my PhD manuscript using classicthesis. I have a few preliminary parts (a summary and a foreword) that I want to include as chapters and sections, but with a different numbering.

I changed the chapter counter using

renewcommandthechapter{alph{chapter}}

before that part, and fixed it so the counter would appear as a lowercase letter in the ToC using

renewcommand{cftchappresnum}{normalfont}

It works well, and in the PDF contents from the hyperref package I do get the right behaviour, with lowercase letters as counters, like this

however, in the main body (on page 8) I get this

and I think some textsc command has overridden the lowercase counter for the chapter. I have tried looking at the tocloft package documentation, to mimick something like the renewcommand{cftchappresnum}{} command, but I haven’t had any luck. The classicthesis documentation doesn’t help either.

I am sure the fix should be quite easy, but I cannot find it.

An illustration of the problem can be reproduced with the following minimal working example,

documentclass{scrbook}
usepackage{classicthesis}

renewcommand{cftchappresnum}{normalfont}
renewcommand{cftsecpresnum}{normalfont}
renewcommand{cftsubsecpresnum}{normalfont}

renewcommandthechapter{alph{chapter}}


begin{document}
tableofcontents
part{Part}
chapter{Chapter}
section{Section}
subsection{Subsection}
Problem: TOC displays Subsection a.1.1., but above it's {textsc a}.1.1.
end{document}

documentclass{scrbook}
usepackage[palatino=false]{classicthesis}
usepackage[sc]{mathpazo}

renewcommand{cftchappresnum}{normalfont}
renewcommand{cftsecpresnum}{normalfont}
renewcommand{cftsubsecpresnum}{normalfont}

renewcommandthechapter{alph{chapter}}

titleformat{section}
    {}{thesection}{1em}{spacedlowsmallcaps}
% subsections
titleformat{subsection}
    {}{thesubsection}{1em}{normalsizeitshape}
% subsubsections
titleformat{subsubsection}
    {}{thesubsubsection}{1em}{normalsizeitshape}



begin{document}
tableofcontents
part{Part}
chapter{Chapter}
section{Section}
subsection{Subsection}
TOC displays Subsection a.1.1., which is what we get now.
end{document}