I understand you have a contact with two phone numbers saved, but regardless of which number you choose, the message goes to the same conversation. This definitely shouldn't be happening!
Here are a couple of ways to diagnose the issue:
Test with Siri:
- Open Siri by pressing and holding the side button (or the home button on older iPhones) or saying "Hey Siri."
- Ask Siri to "send a message to [Name of contact]."
Siri should recognize the duplicate numbers and present you with both options to choose from. Selecting the desired number here will confirm if iMessage is truly ignoring your selection within the Messages app.
Check iMessage Settings:
- Go to Settings > Messages > iMessage.
- Ensure "Send as SMS" is enabled. This allows iMessage to automatically switch to SMS if the recipient isn't using iMessage for a specific number.
If neither of these steps resolves the issue, it might be a bug with the iMessage app. Here's what you can do next:
- Force Quit and Relaunch Messages: Close the Messages app completely (swipe up on the app preview card in the App Switcher) and then reopen it.
- Restart your iPhone 15 Pro: A simple restart can often resolve temporary glitches.
- Update to the Latest iOS Version: Go to Settings > General > Software Update and install any available iOS updates.
By trying these suggestions, we should be able to pinpoint the reason behind the single conversation with duplicate numbers and get your iMessage functioning correctly.