> *ERROR*: Wrong type argument: listp, <<<<<<<
This is a conflict marker. Someone accidentally failed to resolve
a conflict and committed the merge with such markers still present.
This doesn't have to be in code related to Magit, it might be in
any code that, for whatever reason, gets loaded when using the
emacsclient and/or loading a Magit library.
Search (rgrep) all directories that contain elisp code and fix the
issue.