Hello Biomaschine,
I ran some tests and found that the issue lies with the option ‘Crack Free Displacement’ within your material’s properties. This is causing your landscape to essentially flatten out your displacement whenever it is enabled. I ran some more tests to see if this affects other assets like static meshes, and it appears to only occur with landscapes. More than likely due to the way we choose to tessellate the nearest LOD, but that is just a guess. Use the link below to track the report I logged for this issue.
For now, I would just disable the ‘Crack Free Displacement’ option, and be sure you are not pushing the vertices too far to create cracks in your landscape. An increased tessellation value should help mitigate some of this effect, but also be careful with the amount of tessellation you use as performance can become a concern with too high of values.
Let me know if you have further questions or need additional assistance.
Cheers,