This white behavior is as design. Indeed only manipulating exposure allow to properly see the result. We have started a work in this sense to try to have a good exposure for the preview by default, but it is a feature request, not a bug.
Steps
open repro project
open sample scene
in hierarchy, select "Reflection Probe"
in inspector, click Reflection Probe > Bake
in inspector, check the preview
Expected: probe shows skybox
Actual: probe is white
Repro: 2023.3.0a1
NOTES
workaround = reduce exposure manually in the inspector
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