Problem with multiple posts a day

I’m using WP 1.0. When I post two posts a day, I notice that I have a problem with the date of the first post I made: it just doesn’t display. I get to see the hour of the post though ?? When I change the date of one of the posts using ‘Edit timestamp’, it works again and displays the dates.
Are you aware of this problem? Is there a fix for this?
My blog can be viewed at https://www.mathibus.com (just click my ugly face to enter the blog ;)). The two posts are https://www.mathibus.com/blog/index.php?p=8 and https://www.mathibus.com/blog/index.php?p=9.
Greets,
MaThIbUs
P.S.: Happy birthday Matt! ??