Hi @Clapp_Prod, welcome to the community 
It seems you have one item coming from your “Now CET” node, but 3 items coming from the “Last notif CET” node. Assuming the the “Last notif CET” node is the node connected to your IF node this comparison will probably fail for the reasons I’ve described here.
Is your “Now CET” simply returning the current timestamp? If so, you could consider just using an expression of {{ $now }} instead of having another node for this (the docs on $now are here).