Emails sent to wrong subscribers when posting under Gutenberg

I previously reported emails are not being sent to correct subscribers.

I find that when a new post is made, emails are sent to those subscribed to the category Uncategorized, regardless of the categories the post is subscribed to. [On my site Uncategorized has an ID #1]. If I change the status of a post back to Draft and then republish, emails are sent to the correct subscribers.

Working with @mattyrob we have determined that this is a Gutenberg issue arising from the way Gutenberg uses the REST API. This will likely not change.

So this plugin needs fixing to work with Gutenberg, please @collizo4sky
Thank you.