It's a bit strange this is only happening at some places on the airport and only in the 2D cockpit.
The scenery respond differently to the zoom setting, and all objects in the scenery are optimized for fps to disappear if out of view, based on realistic zoom settings, which are usually around 0.70 in the VC.
Although it's possible to go up to 0.50 in the VC without having lines disappearing, in the 2D cockpit, since it deforms perspective, the zoom settings behave differently, so the zoom ratio must be higher while using the 2D view, about 0.90-1.0
Since the vast majority of users use the VC, especially when taxiing, we optimized the scenery to be visible with a realistic zoom setting on the VC. As usual, everything in the scenery it's made for a reason, usually because of performances.