Samsung S9 WhatsApp Inconsistent Sound Notifications

[SunsetZed]

For the last few months I've been having a problem where sometimes I won't get a sound notification when I get a WhatsApp.

It happens with Group Conversations and direct messages. Sometimes it happens with the first message whereas sometimes I get a notification and then in the middle of a conversation.

The message notifications always show up on the home screen but the sound appears to be intermittent and it's driving me bonkers!

[Corso Marche]

Happens the odd time with me too.

Notification without sound. A few times a week maybe, can't identify any trend to it. Pixel 2XL, so other than android and WhatsApp I'm not sure if we've any other commonalities.