Thank you for reaching out. I can certainly understand your frustration with the double voicemail notifications and would be happy to look into this further for you. Next time you experience this symptom, can you please provide me a picture of what you are seeing for double notifications?
Reproduce issue then report to Samsung Members app > Get Help > Error Report
What is the device model number and software version (settings > about phone > software information > build number (last 4 digits)) ?
This is happening on my Galaxy Note 10+ as well. Duplicate notifications, as well as two of the same message in Visual Voicemail. My carrier is QLink, who uses T-Mobile networks. (I've heard of a LOT of problems for Samsung users on any carriers that use T-Mobile's towers (as well as the ones they acquired from Sprint). Might be a whole systemic issue there...? Or is this happening on other phone networks too?