Apple Maps: Siri only says "starting route to ..." then never says anything else unless I turn spoken directions off, then on again.

As the title says, when use Apple Maps for directions, Siri announces "Starting route to ..." then goes silent. The spoken directions setting is ALWAYS set to speak all directions. I have never seen Maps open showing spoken directions set to anything but the first setting.

The only way I can get Maps/Siri to narrate the directions is to select either 'speak alerts only' or 'do not speak directions,' then switch back to 'speak all directions.' Immediately after switching back Siri will speak the first steps and (usually, though not always,) continue to narrate the rest of the route.

I have also noticed that sometimes Siri will speak directions from the start, but it is never consistent and I can't figure out what magic steps make it do this. Regardless, it never remains in this mode. It doesn't matter if I have left Maps open (background) or swiped/closed it & reopen it, it will still only occasionally start narrating without my switching to alerts or silent and then back to speak all directions. This isn't aggravating, unexpected and rather dangerous behavior, as I have to stop driving and mess with the app.

I've tested this on two different iPhone 7, both running iOS 15.5, but this issue has occurred for quite some time. I've tried deleting and reinstalling Maps, rebooting phones, disabling WiFi, disabling Bluetooth, disabling both WiFi and Bluetooth, turning the "silent" ringer switch on side of phone off/on - none of these appear to make any difference.

Please, someone, help me "stop the insanity!" 🤪