Hey Krakean -
This is a known issue with Occlusion currently. The pivot of your mesh is on the camera’s frustum line and the engine is trying to both render and not render the mesh each frame which causes the flickering. However there are two current workarounds that will fix this issue, one is to enable HZBOcclusion via the console or a console variable (r.HZBOcclusion 1) or increase the scale bounds of the item that is flickering. Both of these options have some drawbacks, the HZBOcclusion was turned off in 4.6 because of some development issues with items not occluding correctly and this is one of the items that is currently being worked on. Increasing the scale bounds will keep the item from culling correctly and placing an extra item in the engine’s render pathway for a longer period of time.
As I have said though this is a known issue and is currently being worked on.
Thank you
Eric Ketchum