Double check your reflection capture, with SSR off you should be seeing the capture’s reflection on the floop, but it looks entirely missing.
Here’s a short summary of how reflections work in UE4:
There are two “sources” of reflection: SSR (screen-space reflections) and reflection captures (cubemaps). They are intended to be used together and neither of them are capable of replicating perfect mirrors.
As the name implies, SSR uses image you see on the screen to try to get reflections from. Therefore, it can only display reflections for rays that can hit visible surfaces inside the view frustum, using some algorithms to fill the gaps (the stretching effect). This is why the painting is cut-off: if the camera can’t see it, it cannot be reflected. SSR is best suited for “contact reflections” on materials that display fuzzy reflections that quickly fade out as the reflected objects get further from the reflecting surface.
Reflection Captures are generated offline, by taking a 360 degree picture from their center and saving it into a cubemap texture. During rendering, rays are reflected into the reflection box/sphere to sample from the cubemap texture. Therefore, reflection captures are better suited for reflecting elements that are either on the surface or outside their box/sphere.