I've said this before, but it's the lag time in officially recording deaths. The actual date of deaths would show a longer line representative of a top of a mesa, and a steeper drop to today.
I've also pointed out some of the "at least it's useful" graphs the people who are "very concerned" about how data is released and presented to the media, so here are a couple more.
First, actual date of death in Florida
Second, graph showing the increasing lag in recording data. You can see that when the wave started in July, most deaths were recorded within 5 days. Now it's stretched to almost a month.