Hi bryanvillarin
Thanks for your comments. For the recent post, unfortunately I already posted the link in social media by hand (I do not like using publicize) after changing it, so to fix the email notification I would ruin it for far more of my readers..
:-)
But for moving forward, I will try to change the time zone (in fact I should change it anyways because I've been living in Norway for 6 months).
One idea. Is it possible that this happens when I copy an older post to start a draft for a new post? It occurs to me that for at least this one I did it. Perhaps the other one too. This may mean there is a bug with that feature.
What do you think, is there any way to test it?