Error of array_intersect_key(): Expected parameter 1 to be an array in admin

Hello! Our client is using this plugin, after tracing the bug code. It come from the WSCCS because it supplies the following string instead of an array.

In the admin page, when we edit a page, before the editor is loaded, the following error is displayed:

Warning: array_intersect_key(): Expected parameter 1 to be an array, string given in /public_html/wp-includes/rest-api/class-wp-rest-server.php on line 1424

We tried to deactivate it and the error is gone.
While we are not sure why it give this error because it does not appear in other site with similar configuration.

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