I am having the same issue since updating to WP 5.9. If I echo $block[‘anchor’], it shows in the editor right after saving, but when viewing the page, or reloading the edit screen again, the anchor is gone. The anchor string is also gone from the “HTML anchor” value in the Block’s Advanced Settings.
Anchor values remain for core WP blocks.
I have the following set in acf_register_block_type: ‘supports’ => array(
‘anchor’ => true
)
And the HTML Anchor text box shows in the Block Advanced Settings. It just does not persist.
I also do not see ‘anchor’ as a property outputting var_dump($block)
