bug#58233: Latex style files shifts code with underscores

[uzibalqa]

I am working on some latex style files and have noticed that code with 
underscores gets displayed
as subscript notation (characters get shifted downwards) rather than showing 
code as it should be.

Consequently, the following looks extremely weird.

\cs_new_protected:Nn \__hagbard_newtheorem_parent:nnn
 {
  \newtheorem{#1_inner}[#3]{\color{\l__hagbard_theorem_setcolor_tl}#2}
 }
\cs_generate_variant:Nn \__hagbard_newtheorem_parent:nnn { VVV }