Black holes on my foliage mesh that are flickering when moving the camera(only on meshes painted in foliage mode)

I’m encountering this issue while using foliage painting mode on my landscape .

However, I noticed that this issue disappears when I manually place the foliage meshes on the landscape. It seems to be only happening when I’m painting them using the foliage tool. (I am using Forward Shading).

I would appreciate any suggestions or solutions that could help me resolve this issue. Thank you in advance for your help!