This is a long standing bug with the engine and is not related to screen size LODs:
It turns out that there is a minimum number of lights in the view above which the engine switches to Tiled Deferred Shading, which is 80 by default if I am not mistaken. Evidently, in this shading mode, light sources with a length associated with them are (erroneously?) rendered as point light sources.
We could raise this minimum amount of lights, but only if there is no noticeable performance cost, which I would need to investigate.