sqlite3_bind_text replaces first char in string with NULL when used in function

I'm trying to pass a string to a function that uses sqlite3_bind_text. When I check the database, the first char of the string is replaced by a unicode NULL char (if I interpret the rectangle symbol containing four zeroes in each corner correctly).

Here is a minimal example. The cout in the function outputs the string correctly, as does using sqlite3_bind_text directly in main.

#include "sqlite3.h"
#include <iostream>

using namespace std;

void bind_string_to_statement(sqlite3_stmt *& statement, const string s)
{
    // This replaces the first char in s with [0000]...
    sqlite3_bind_text(statement, 1, s.c_str(), -1, nullptr);

    // ...although this looks fine:
    cout << s.c_str() << endl;
}

int main()
{
    sqlite3 * db = nullptr;
    sqlite3_open("test.sqlite", &db);

    sqlite3_stmt * statement = nullptr;

    string query
    { "create table if not exists t(key text primary key not null, value text)" };
    sqlite3_prepare_v2(db, query.c_str(), -1, &statement, nullptr);
    sqlite3_step(statement);
    sqlite3_finalize(statement);

    query = "insert or replace into t(key, value) values(?, ?)";
    sqlite3_prepare_v2(db, query.c_str(), -1, &statement, nullptr);
    string s{ "stuff" };

    // This fails as described in the function above...
    bind_string_to_statement(statement, s);

    // ...although this works fine:
//  sqlite3_bind_text(statement, 1, s.c_str(), -1, nullptr);

    sqlite3_step(statement);
    sqlite3_finalize(statement);

    sqlite3_close(db);

    return 0;
}

What could be the problem when using sqlite3_bind_text in a function?