Choice of publication in a register post type

Hello, I created a flexible content field with acf on WP and all my sections are well configured on pinegrow. On the other hand I have a problem on a section where I created a register post type which is set up with acf fields… I chose to activate the relationship field in ACF and a show post in pinegrow but it doesn’t work? I don’t understand or I make the mistake because when I remove the field from my flexible content in ACF it works?

Is it possible that the customer can choose the post he wants to display by another method?

If anyone has any ideas, I thank you because I’ve been pulling my hair out for a few days now.

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