Disabling DFAO prevents landscape from contributing to Lumen scene

From licensee:

We disabled DFAO on our project (using r.DistanceFieldAO 0) to replace it with Lumen occlusion, as the combination of both was creating dark blobs under bushes and grass. However, we noticed disabling DFAO removes the landscape from the Global Distance Field, which has other side-effects such as the landscape not contributing to the Lumen scene. This is easily reproducible in a test map in vanilla UE5.2/5.3 (see screenshots below).

Is this behavior intended? Is there any way we can bring back the landscape in the GDF without DFAO?

• Create a level and add a landscape and then a cube for comparison.
• Change view mode to Lumen Overview.
  • Notice both Landscape and cube are shown in each view still.
• Disable DFAO using the CVar 'r.DistanceFieldAO 0'.
• Reload the level. Could also back away some distance from the objects and then focus on them.