Flashing black out

[crashtopher]

My screen keeps flashing in and out to half black screen any one have this issue?

[kimberleigh]

What series and has the phone had any damage or impact?

[meself]

Run the diagnostic test i would also submit feedback

[MrGhoul]

Try wiping the "cache partition" to see if that helps. It's safe and won't remove your settings or app files. Clearing the "cache partition" can help resolve any issues caused by old or corrupted system cache data. 

Follow the steps below,

Clear the cache partition
- Turn the phone off (shut down)
- Press and hold the Volume Up key, then press and hold the side key.
- When the Android system recovery menu options show release buttons.
- Press the volume down key several times to highlight wipe cache partition.
- Press the side key to select.
- Press the volume down key to highlight yes, then press the side key to select.
- When the wipe cache partition is complete, Reboot system is now highlighted.
- Press the side key to restart the device.

If clearing cache partition didn't help, try booting in safe mode
BOOTING IN SAFE MODE
- Press and hold the Power button
- Tap and hold the "Power off" option that appears
- Tap safe mode to proceed
- you will now be in safe mode
- while in safe mode, see if you experience the flashing black screen.
Safe Mode will disable all third-party apps on the device. If the flashing black screen doesn't appear in safe mode, then a third-party app is the culprit and causing it.

Submit feedback(error report)
https://www.samsung.com/ae/support/mobile-devices/raising-an-error-report-via-samsung-members-app/