Yes, as I suspected the problem is the size of the sphere reflection captures. When part of the capture expands beyond the wall you will see the “reflection” from outside being projected inside. I fight this problem by placing a smaller captures that covers only the problematic areas.
Now its a bit different with planar reflection capture though, when you use it you dont need to use the sphere reflection captures on walls or floors, but only on places where its needed to have reflections. For example the legs of the chairs are metalic and they need reflections so I add a reflection capture to only cover the table and chairs if you get what I mean. 