I have the similar setup, and after updating home assistant core to 2022.5.1 I have noticed a new network tab on the settings->system page which says “external access disabled”
After entering my URL and saving, it still shows as disabled.
However, I’m able to access my instance externally. my implementation uses duckDNS & Nginx reverse proxy.
Another point to note, I did have an issue while accessing the instance with the companion app on IOS prior to the update, it was giving me an SSL error. Deleting the app on my phone and reinstalling helped resolve the issue.