Problem with some kind of shadow LOD

the spot light is stationary, but there’s a weird level of detail issue in the shadowing.
I’m using distant field shadows.

take a look:

this is how it should look like:

… and that’s just a lighting preview. any ideas how to fix those shadows? setting the spotlight as movable works but that’s not the solution I’m looking for. I want baked GI from stationary light with dynamic shadows.

Linking my answer from the Forums where you asked as well: Problem with some kind of shadow LOD - Rendering - Epic Developer Community Forums