RSS feed creation order of operations and issues

Running the latest version of WordPress on WPEngine. We were having occasional issues with articles that were being published showing up in the default RSS feed when they were put, correctly, into a different category and should have only shown in that feed

For instance: article is created and published and has a category of “Misc”. Our default feed “Articles” does not contain any posts from the Misc category. We have an app that pulls from the Articles feed to populate stories in the app. During heavy traffic times, articles from Misc. would show up in the Articles feed.

We have possibly fixed this by not having Articles be the default feed any longer, but are not sure if we have solved this issue or if it may pop back up. The posts with the Misc. category are created by an auto – import feature if that makes any difference.

If you have any deep insight to how WP makes articles and assigns feeds, I’d love to get confirmation that this is, indeed, the solution or if there’s something else we may need to do to mitigate.