They've now made some level of online connection mandatory, as you need an oauth token to connect to the local interface, which you can only get online. That token does have an expiry time of a year, but still, it's a significant step back from where they were before, where you could get local access completely disconnected from the internet (and in fact, those who completely isolated it to prevent it from getting software updates still have this).

I assume the Home Assistant integration is through the Enphase cloud account. Herein lies the peril.