Missing cell values even when there is no inflowing drain ( I think)

[WindingWinter]

I have a terrain that looks like this:

As you can see, the elevation levels peak at the center and then going downwards radiating from the center. I would expect that there is no inflowing drain for this kind of terrain.

And hence, base on #195 and D8ContributingArea guide here, I would expect that the TauDEM should be able to nicely generate all the contributing cells.

But that's not the case! Even when -nc is selected, there are still a lot of cells missing contribution, as shown below:

There are also a lot of missing area if -nc is not set.

Why is this so? Here are my steps, and I've attached the tif file

1. PitRemove.exe Site6.tif
2. D8FlowDir.exe -p Site6.tif -sd8 Site6sd8.tif -fel Site6fel.tif
3. aread8.exe -p Site6p.tif -ad8 Site6ad8.tif
4. Gridnet.exe -p Site6p.tif -plen Site6plen.tif -tlen Site6tlen.tif -gord Site6gord.tif
5. PeukerDouglas.exe -fel Site6fel.tif -ss Site6ss.tif
6. aread8.exe -p Site6p.tif -wg Site6ss.tif -ad8 Site6ssa.tif
7.  Threshold.exe -ssa Site6ssa.tif -src Site6src.tif -thresh 10
8.  Streamnet.exe -fel Site6fel.tif  -p Site6p.tif  -ad8 Site6ad8.tif -src Site6src.tif -ord Site6ord.tif -tree Site6tree.dat -coord Site6coord.dat -net Site6net.shp -w Site6w.tif

Site6.zip

[WindingWinter]

Anyone who can enlighten me on this one?