My wifes Samsung S8+ also has the swipe screen to answer her phone, but winds up calling back the caller. I thought it might be from the Tempered Glass Screen protector. I will try some of the solutions offered by the readers.
This was the picture of my original Note 7, I have since received my safe Note 7 and I'm unable to change the color. I have gone through the steps to change the color to Red and in the process it did turn Red, but even after restart it reverts to White.
I have tried to change my HOUR icon on time to a different color, which worked on my original Note 7, the replacement reverts to white after I go through all the steps.
Anyone able to help or explain.