Using KLCK.
On my home screen at the top I see a single notification, but on the lock screen the message appears twice, under ni(0,icon/title/text/whatever) and ni(1,icon/title/text/whatever). If I have a single unread message that message appears twice, with more unread messages the first (0) says I have x unread messages while the second one (1) shows one of those messages.
Is this a problem with Whatsapp or with KLCK? Or maybe a way to avoid this? It doesn't happen with any other apps (or so far I've found).