Solved! Go to Solution.
That's unusual, @Spills1984, and I have not been able to recreate this either. Is your WhatsApp set up to play a notification sound when you send a message?
From what I understand, you would just need to open WhatsApp. Tap More options > Settings > Notifications > Turn Conversation tones off.
It is strange that it's not happening when using other earbuds. Nevertheless, please let us know how you get on.