Rispondi a "black bar at the bottom screen"I had a similar problem however the lines were appearing at the top. However I noticed a few things it started happening on my MacBook Pro 2017 13” model after the Mojave update also it only happens when I have a black color themed application or a movie with black bars at the top and bottom is played for existing amount of time. The solution I found was shut down the Mac for about an hour or switch to an application which has a complete white or any other color Interface for about an hour then it slowly goes away. Further, I took a screenshot shot on that the normal color apprears. It's an interesting issue. I am not sure what the underlying cause is I have a feeling it could be something to do with both hardware and software.