Blurred External Display On Login Screen

I'm running a Mid-2014 Macbook Pro with 15-inch Retinia display and OS X 10.10.3. Ever since I've been using this unit (purchased around March 2015 time frame). I've had a problem with the external display when I boot up. Initially the external display (a Viewsonic VA2012wb) will be blurred and the built-in display is fine. I can log in and the display returns to normal. Also, if I unplug the external display and plug it back in when the login screen is displayed the resolution resets to normal. I've tried resetting the SMC and PRAM. Also, this wasn't a problem on my other Macbook Pro that ran Mavericks. Ideas?