[Landscape] Is that a bug or am I doing something wrong?

Hi UE4 Community!

I just noticed that my landcape has some weird white flickering when it needs to be suddenly rendered on the screen.

Is there something I can do? Could the dynamic lightning be the problem that I enabled? I just did that because I was getting sick of the lightning building every single time when I changed someting and wanted to see the result.

What’s your system configuration?

Intel Xeon 1230v3, 8GB DDR3, R9 270X 2GB, Win7 x64, 120GB SSD and 1TB HDD

The project is on the HDD and when I builded it(Windows x64), I moved it to the SSD and started it there.