Sorry for my late reply. The interesting thing is that the flickering did not
occur any more since comment 4 was added. I was waiting for the flickering to
occur again before posting the requested info, but it did not until now, so I
will attach the requested info while the flickering is not manifest.

My current versions are:
Graphics:  Card: Advanced Micro Devices [AMD/ATI] Baffin [Radeon RX 460/560D /
Pro 450/455/460/560]
           Display Server: X.org 1.19.6 drivers: modesetting,fbdev,vesa
           tty size: 166x42 Advanced Data: N/A for root

Linux nyx 4.15.17-300.fc27.x86_64 #1 SMP Thu Apr 12 18:19:17 UTC 2018 x86_64
x86_64 x86_64 GNU/Linux