Demo of strange behaviour in KnexJS when inserting into a table whose primary key is a string

gistfile1.js

// Knex 0.4.11
var Knex = require('knex');
var Q = require('q');

var DB = Knex.initialize({
	client: 'mysql',
	connection: {
		adapter:  'mysql',
		database: 'temp',
		user: 'root',
		password : ''
	},
});

var createVanilla = function() {
	return DB.schema.hasTable('vanilla').then(function(exists) {
		if (exists) return Q();
		console.log('govanilla');
		return DB.schema.createTable('vanilla', function(t) {
			t.increments('id').primary();
			//t.dateTime('created_at').defaultTo(DB.raw('CURRENT_TIMESTAMP'));
			t.string('name');
		}).then(function(result) {
			console.log('created vanilla table');
			return result;
		});
	});
};

var createStringy = function() {
	return DB.schema.hasTable('stringy').then(function(exists) {
		if (exists) return Q();
		console.log('gostringy');
		return DB.schema.createTable('stringy', function(t) {
			t.string('id').primary().notNullable();
			//t.dateTime('created_at').defaultTo(DB.raw('CURRENT_TIMESTAMP'));
			t.string('name');
		}).then(function(result) {
			console.log('created stringy table');
			return result;
		});
	});
};

var createTables = function() {
	return Q.all([
		createVanilla(),
		createStringy(),
	]);
};

var insertObj = function() {
	var obj = {
		//created_at: new Date,
		name: 'test',
	};
	console.log('insertObj', obj);
	return DB('vanilla').insert(obj, 'id').then(function(ids) {
		console.log('Inserted', obj, ids);
		return ids;
	});
}

var insertStringy = function() {
	var obj = {
		id: 'string-'+parseInt(Math.random()*1000),
		//created_at: new Date,
		name: 'test'
	};
	console.log('insertStringy', obj);
	return DB('stringy').insert(obj, 'id').then(function(ids) {
		console.log('Inserted', obj, ids);
		return ids;
	});
};

createTables()
	.then(function(result) {
		return Q.all([
			insertObj(),
			insertStringy(),
		]).fail(function(err) {
			console.log('Error inserting rows', err);
		});
	}, function(err) {
		console.log('Error creating tables', err);
	})
	.then(function(results) {
		console.log('inserts', results);
	});