I ended up buying the RCA version anyway and mine does not seem to have that subscriber-not-available announcement. I upgraded the firmware using Hik-connect and it's at 171127.171205 still saying subscriber not available after the ring time out
But the problem is that when someone presses the doorbell, Hik-connect (Android) pops up and the "ringing" sound comes through as media. But my media volume is set really low or silent. Why can't it just ring like a ringer or notification. Then I can set the proper volume and even usr vibrate.