I’m not sure if it is related only to local server links ( Using local server share links - Help - Obsidian Forum), but if there is an underscore in the link, then \
that is before the underscore, gets missing, eg:
[_closed-protocols](file:///\\\fileshare\shared\...\data-submissions\_closed-protocols)
link will be rendered in preview mode as:
[_closed-protocols](file:///\\\fileshare\shared\...\data-submissions_closed-protocols)
You can temporarily solve the problem by adding extra \
:
[_closed-protocols](file:///\\\fileshare\shared\...\data-submissions\\_closed-protocols)