Different font size in same list

[edoardottt]

This is the code:

%-----------EDUCATION-----------------
\section{Education}
    \resumeSubHeadingListStart
    \resumeSubheading
      {Sapienza University}{Rome, Italy}
      {Master's Degree in Cybersecurity; 109/110}{Oct. 2020 -- May 2023}\\
      \vspace{0.3cm}\small{Dissertation: "Proposal and Investigation of a framework for Cross App Poisoning\\attacks detection in Software Defined Networks."}
    \resumeSubheading
      {Sapienza University}{Rome, Italy}
      {Bachelor's Degree in Computer Science; 103/110}{Sept. 2016 -- Oct. 2020}\\
      \vspace{0.3cm}\small{Dissertation: "Design and development of the End User Development system in SeismoCloud".}
    \resumeSubheading
      {Fabio Besta Scientific High School}{Orte, Italy}
      {Scientific High School Diploma; 71/100}{Sept. 2011 -- July 2016}
  \resumeSubHeadingListEnd

and this is the result:

Why the first item is bigger than others? How to change this?