Rectangle disappearing after down-right motion

My assignment for this week is to generate and animate a bunch of rectangles. Each rectangle starts from a random location and has a random speed and direction. When a rectangle goes DOWNLEFT, it seems to disappear and never show up again. Here is my Rectangle class (including drawing code):

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// Module: RectangleClass.h
// Project: CIS023_F2016_Lab_14 Montana Burr
// Developer: Montana Burr
// Date: December 8, 2016
// Purpose: Header file for RectangleClass

#pragma once
class RectangleClass
{
public:
	RectangleClass();
	void Draw(HWND, HDC); // Draws rectangle on main window.
	~RectangleClass();
	RectangleClass *nextNode; // Next rectangle in linked list
private:
	POINT pLocation; // Initial location of rectangle.
	POINT pSize; // Size of rectangle.
	COLORREF color; // Color of rectangle.
	int direction; // Direction of animation.
	int speed; // Speed of animation.
};

// Module: RectangleClass.cpp
// Project: CIS023_F2016_Lab_14 Montana Burr
// Developer: Montana Burr
// Date: December 8, 2016
// Purpose: Defines functions for RectangleClass class

#include "stdafx.h"
#include "RectangleClass.h"


RectangleClass::RectangleClass()
{
	// Seed the random number generator with the current time.
	srand(time(NULL));
	// Initialize member variables to random values.
	pLocation.x = rand() % 100 + 1;
	pLocation.y = rand() % 100 + 1;
	pSize.x = rand() % 100 + 1;
	pSize.y = rand() % 100 + 1;
	int red = rand() % 255;
	int green = rand() % 255;
	int blue = rand() % 255; 
	color = RGB(red, green, blue);
	speed = rand() % 20 + 10;
	direction = rand() % 7;
	nextNode = nullptr;
}

void RectangleClass::Draw(HWND mainWindow, HDC hdc)
{
	// Get the rectangle that contains the window.
	RECT rClient;
	GetWindowRect(mainWindow,&rClient);
	// Animate pLocation
	switch (direction)
	{
	case UP:
		{
			// Move rectangle up
		pLocation.y -= speed;
		if (pLocation.y <= rClient.top)
			// Bounce rectangle off top border of window
				direction = DOWN;
		};
		break;
	case DOWN:
		{
			// Move rectangle down.
			pLocation.y += speed;
			if (pLocation.y + pSize.y >= rClient.bottom)
			// Bounce rectangle off bottom border of window
				direction = UP;
		};
		break;
	case LEFT:
		{
			// Move rectangle to the left.
			pLocation.x -= speed;
			if (pLocation.x <= rClient.left)
			// Bounce rectangle off left border of window
				direction = RIGHT;
		};
		break;
	case RIGHT:
		{
			// Move rectangle to the right.
			pLocation.x += speed;
			if (pLocation.x + pSize.x >= rClient.right)
			// Bounce rectangle off right border of window
				direction = LEFT;
		};
		break;
	case UPLEFT:
		{
			// Move rectangle up and to the left.
			pLocation.y -= speed;
			pLocation.x -= speed;
			if (pLocation.y <= rClient.top)
			// Bounce rectangle off top border of window
				direction = DOWNLEFT;
			else if (pLocation.x <= rClient.left)
			// Bounce rectangle off left border of window
				direction = UPRIGHT;
		};
		break;
	case UPRIGHT:
		{
			// Move rectangle up and to the right.
			pLocation.y -= speed;
			pLocation.x += speed;
			if (pLocation.x >= rClient.right)
			// Bounce rectangle off right border of window
				direction = UPLEFT;
			else if (pLocation.y <= rClient.top)
			// Bounce rectangle off top border of window
				direction = DOWNRIGHT;
		};
		break;
	case DOWNLEFT: 
		{
			// Move rectangle down and to the left.
			pLocation.y += speed;
			pLocation.x -= speed;
			if (pLocation.y + pSize.y >= rClient.bottom)
			// Bounce rectangle off bottom border of window
				direction = UPLEFT;
			else if (pLocation.x <= rClient.left)
			// Bounce rectangle off left border of window
				direction = DOWNRIGHT;
		};
		break;
	case DOWNRIGHT:
		{
			// Move rectangle down and to the right.
			pLocation.y += speed;
			pLocation.x -= speed;
			if (pLocation.y + pSize.y >= rClient.bottom)
				// Bounce rectangle off bottom border of window.
					direction = UPRIGHT;
			if (pLocation.x + pSize.x <= rClient.right)
				// Bounce rectangle off right border of window.
					direction = DOWNLEFT;
		};
		break;
	default:
		break;
	}
	// Draw the rectangle.
	RECT mainRectangle = { pLocation.x, pLocation.y, pSize.x + pLocation.x, pSize.y + pLocation.y };
	HBRUSH brush = CreateSolidBrush(color); // Set fill color of rectangle.
	HPEN pen = CreatePen(PS_SOLID, 1, color);
	SelectObject(hdc, pen); // Select pen for drawing border.
	FillRect(hdc, &mainRectangle, brush);
}

RectangleClass::~RectangleClass()
{
}


Checked my break statements, they're all there.
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