Mine did the exact same thing with the update...go to: Settings > My Device > Accessibility > Flash Notification (near the end of the list) uncheck the box next to it. It is a setting intended for the hearing impaired so the phone flashes when a notification comes in. I'm not sure why it is a default setting, seems like you would have to turn something like this on, but instead it is on by default.
Thanks for the fast response. I spoke to Samsung and that is what they said as well. The strange thing is, that flash notification was NOT Checked on my phone. Samsung said for me to check it "ON", then unchecked it. That stopped it so I'm happy. Verizon level 2 tech said his coworker had same problem and did factory reset to stop incoming call flashing. Seems Verizon doesn't know about this glitch yet. Thanks again.