Hey Deep_Sea_Diver, thanks for reaching out and welcome to forums!
So that we could get a better idea about this, may I ask you to clarify a few things:
1. Is that the only map you've encountered issue with or does it happen in any map?
2. Did the lines you're referring to flicker or was it solid?
3. Have you tried changing your graphics settings (let's say reducing settings to lower ones), to see if problem remains?
4. Are you using PC or Notebook?
5. Did the issue occur as soon as you've loaded into the game or did it start to happen gradually?
6. Are you using Vulkan or DX api?
Let us know and we will have a look!