AMP shows blank page when article use classic wordpress editor

Hello
I think it comes from one of the last updates but I discovered that article made usin the old classic editor of wordpress are showing a blank page instead of the amp page.
When I change the editor in the article and transform the classic editor into bloc from Gutenber and save the article, the AMP page works…

Here are some example :
a working AMP page : https://www.byothe.fr/2020/07/dzook-une-ia-qui-transforme-vos-portraits-photo-en-dessins/amp/
a not working amp page : https://www.byothe.fr/2019/12/imprimer-une-page-web-entiere-en-pdf-avec-pdf-cyborg/amp/

Is ther something I should do or is it a bug ?

Thanks

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