I've heard about wrong timezone issues here before. Can you verify that you have the correct timezone set at Runalyze? https://runalyze.com/settings/account
(It's from the Health Snapshot feature, never from nightly sleep measures)
I hoped that it will come end of this month, but as I have 4 days vacation this could get a little bit tricky. I still have to finalize it, but it's within reach