Answered question
Received my first voicemail ... I got multiple notifications (3). Thought that was strange. Anyone observe such a behaviour.
Yes it can happen when there is weak signal.
Your phone does not acknowledge the text/notification, so it is reloaded to your phone.
Other answers
Try restarting your phone, it may fix this issue.
Here it’s normal...
Same, I get a voicemail notification every time I go into my underground parking or when I slip into areas with little or no coverage.
However, this is often the case with any carrier