Hello, I just wanted to share my experience with this bug/glitch and how I fixed it. The very next day after I bought the s8+, it started to present the flickering screen error, after a lot (I really meant a lot) of testing, either in safe mode or not, the problem persisted. a few days later I had a hunch with the network connection, and now I can confirm this problem shows up whenever the cell phone tries to connect to the gsm network, as the options in network selection are lte/wcdma/gsm in the settings, this was a kickback.. so after looking a little in the play store I found an app that allows you to select/force any type of network. After downloading it, I just selected lte/wcdma and now works perfectly.
I did select several times just the gsm network just to be sure this was the bug/glitch trigger, and indeed it is. the app itself is 4g switcher. Feel free to ask any other Q’s.