Struggling with table headers

Yannig Robert via "Users of the Lout document typesetting system." <[email protected]> Thu, 20 Feb 2020 00:51:12 +0100

Newsgroups	gmane.comp.type-setting.lout
Message-ID	<[email protected]>

Hello,

I am having a fight with table headers, for some reason, they "move up" 
to the previous page. You can find an example there : 
https://www.dropbox.com/s/d2655rfht8uagi7/Memento_4.txt.ld?dl=0

Do you know what I am doing wrong?

Regards

Yannig