AW2521HFL, horizontal lines, Streamlabs OBS

I brought my Alienware AW2521HFL AMD FreeSync (G-Sync compatible) in Kuwait.

I setup my AW2521HFL to 240Hz and conducted color management calibration. I downloaded the driver and device manager shows the AW2521HFL. But I found my display to look dull and less saturated icon that have a pastel look to them. I restored to default and found no change. During gaming, colors look good. But my desktop icons don't show good colors. 

I am a streamer using Streamlabs OBS for broadcasting. gaming looks wonderful. Two days later my AW2521HFL started showing horizontal black lines. I closed my Windows and unplugged cables and ran the diagnostics test. Everything seems fine. I use another DisplayPort on my Nvidia RTX 2070 Super and screen didn't show any horizontal lines.

When I only use Streamlabs OBS, again the lines start building up getting darker. It doesn't happen with any other application. So I reinstalled Streamlabs OBS and found the issue to be recurring. 

I even put a dark color wallpaper to check but no lines show up. The AW2521HFL is 7 days old today and I want to know how to fix this. I would love to use it but if this issue can't be fixed I'd like to return it. Refurbished is not something I'd go for. But please help me in this unfixable situation.