Would you mind showing me how you have your material set up for your characters hair?
Also, take a look at the two documentation links below which elaborate on how to use Sphere Reflection Captures correctly and effectively.
Sphere Reflection Capture Actor
Let me know if you are still having troubles getting your reflections to function properly. Be sure to turn on ‘Screen Space Reflections’ within your levels ‘Post Process Volume’ if one exists in your scene.
I think you are mixing up screenspace reflections and the captured sphere reflections.
Whenever screenspace reflections are enabled, the screenspace reflection will override the sphere reflections, and the sphere reflection will be used anywhere that is reflected offscreen.
I think what you are seeing above is actually screenspace reflections not the sphere. As suggested make sure you try going to Show->LightingFeatures-> ScreenSpaceReflections and uncheck the box to isolate the issue.
The sphere reflection actor should always capture the translucency. Screenspace reflections will only capture the translucency if “RealTime” is enabled as well as TemporalAA (Show->AntiAliasing).
However the accuracy of reflected translucency in screenspace reflections is not going to be as good as the opaque geometry so you may see something weird like the window pane not being in exactly the right spot