Horizontal Thin Grey Lines Across

Hi,

On initial startup of my MacBook, or lifting up the lid from sleep, thin grey/black lines appear across the very top of my screen. After several minutes the lines slowly fade until they disappear.

I have reset the NVRAM, SMC and also re-installed the operating system yet the issue still occurs.

What I am struggling to decide on is whether the fault is due to a hardware issue or technical issue. Due to the fact that the lines disappear after the monitor being active for a little while I am presuming it is a hardware fault.

I purchased the MacBook in September 2017, and had to have a screen replacement in December 2017 because of another hardware issue that was unexplainable.

Any support would be much appreciated!

Thank you in advance.