When run on MacOS disfetch prints part of it's switch case code instead of evaluating it and not printing packages line. MacOS uses bash 3.2 as it's /bin/sh, and if I use zsh as shell the problem is no longer present. So it seems like the problem is with older versions of bash
The same result occurs with bash 3.2 on a different machine

Most likely this is because older bash confuses closing bracket in switch case as the one closing command substitution, and treats everything afterwards as a string