[chaley]

The problem happens because the template function uses lstrip() to remove the prefix. That function doesn't look for a string but instead strips out each character (case sensitive). Your user category is Pseudo so if an author begins with any of those letters (note that P is one of them) then it will be stripped. If an author name started with d then the same thing will happen.

This fixes it by changing lstrip() to a slice, removing N characters from the beginning where N is the length of the outer user category name passed to the function (user_cat_prefix). As a side benefit it will be a bit faster.

def evaluate(self, formatter, kwargs, mi, locals, val, col_name, user_cat_prefix):
    new_val = ''
    if hasattr(mi, '_proxy_metadata'):
        all_cats = mi.user_categories
        cats = {k:v for k,v in all_cats.items() if k.startswith(user_cat_prefix)}
        SEP = mi.metadata_for_field(col_name)['is_multiple'].get('list_to_ui', '')
        new_val = set()
        if SEP:
            val_ = val.split(SEP)
        else:
            val_ = [val]  
        prefix_length = len(user_cat_prefix)
        for user_cat, v in cats.items():
            repl = user_cat[prefix_length:]
            for user_cat_item, src_cat in v:
                if src_cat == col_name:
                    for item in val_:
                        if item == user_cat_item:
                            new_val.add(repl)
                            val_.remove(item)
                        else:
                            new_val.add(item)
        if new_val:
            return ', '.join(list(new_val))
    return val