How can I handle this Depth Of field foreground issue?

Hello try the following commands:

r.MotionBlurQuality 4
r.MotionBlurSeparable 1
r.DepthOfFieldQuality 4
r.ForceLOD 0
r.TemporalAA.Upsampling 0
foliage.ForceLOD 0

Also have in mind there is a bunch of possible causes, for example the Current Aperture of the camera perhaps is too low:

If I increase:

Another possible reason is the material is using embed alpha instead a proper independent opacity map, which causes it loads twice the texture, or configuration itself is not good:

Hope it helps!