When first starting the beta the sky seemed to be working fine but for some reason the sky is completely black but the lighting from the sun seems to still be affecting the landscape. Also something I found was that you can see the blue sky and the sun in reflections such as glass and water reflections.
Thank you for your report!
This issue has already been mentioned in the list of known issues, so we won't be tracking it in JIRA: http://aka.ms/rtxbeta
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