Quite confirmed that it's ghosting caused by the (UV?) filter.
Just look at the reflection symmetry which is typical of ghosting : The blue artifact line on the left bottom is exactly the outline of the roof top at the right top area. Likewise, the blue artifact line on the top right side area is exactly the reflection of the outline of the building's roof top at the bottom left. In ghosting, a reflection of bright light source in the picture can be found at the opposite side of the frame.
Basically, it's a tiny reflection (of bright light source in the picture) that's bounced off from the front glass of the lens, onto the inner side of the (UV?) filter and reflected then back into the lens and onto the sensor.