Delay Between Messages for Notification Block Not Functioning Properly?

I have set the "Delay Between Messages (sec)" to 600, but it doesn't seem to have any delay when moving down an on-call roster. I've tested the pipeline on Ignition using two people on a roster. It notifies both of the people and moves onto the next block within 10 seconds. I have included an image of what is said about the delay function for reference.