Verizon Galaxy S3 - Stock Email app flashes on and off while on a call

[Dansole]

I tried to access my stock email app while I was on a call and it flashes on and off (black screen) - soon as I was off the call it was fine.
Not sure if it was because of the update but I'm almost sure that this didn't happen before.

Any suggestions?

Thanks
Dan

UPDATE - Turns out I had "Turn off screen during calls" in settings - but when I was flipping phone down in order to view screen my thumb was covering the sensor on the upper right side of the screen causing the screen to turn off - and it was not only the email program but any of the apps.