Ambient Occlusion with dynamic mesh interaction not working

Good morning,

I am working on a project where there’s a lot of sequences and animations. I’ve been using SSAO and DFAO to add ambient occlusion in my scenes. It’s working quite nicely for the environment. The problematic is that where there should be contact with dynamic objects and the landscape, or if 2 characters are interacting with one another, there’s no ambient occlusion.
It looks a bit better when I enable DFAO, but it still lacking the AO from contact with ground or dymanic object. And when I’m rendering my sequence, there’s a lot of ghosting in frames.

I can’t show any screenshots, so I’ll use one from the sequencer example of UE4.

I would really appreciate your help, I’ve been trying to fix this for many days.

Thank you for your time and your help