Missing voicemail notifications on iOS 26

I was waiting for calls from my doctor. Phone, tablet and Mac never showed a missed call. Only on my iPad did a notification pop up with a summary of a new voicemail from my doctor. When I opened the voicemail via the notification, there wasn’t a new voicemail in the phone app. This was on iOS 26. I have received spam calls and normal calls on 26 before this issue.

Is this a known issue on 26? This is very frustrating as I need to be able to take calls from my doctor.

[Re-Titled by Moderator]

Original Title: Voicemail not showing