Wrong Canonical url link

You need to reset your indexables. There are a couple of ways to do this – you can use a WP-CLI command (wp yoast index), or you can use the Yoast Test Helper plugin.

If you install the Yoast Test Helper Plugin, you can go to Tools > Yoast Test. In the “Yoast SEO” box with a bunch of buttons, use the “Reset Indexables tables & migrations” button to flush them. You can then uninstall the plugin, remove your manually-entered canonical URL, and the default (autogenerated) canonical URL will be fixed.

Theoretically, anytime you make a change such as changing a parent page URL, that should trigger Yoast to automatically update its indexables. So it may be worth opening a GitHub issue so they’re aware this didn’t happen as intended.