Node with no coverage (dc) on its own rank

[jp-jong]

Hi @lh3!

Previously, I generated a graph with 6 assemblies in total and when I tried to use -x asm --cov, there are some nodes whose rank is itself but the dc tag value is 0. Below is a screenshot of an example,

Additionally, many of these nodes are surrounded by fragmented and short nodes as shown in the screenshot below. Those colored in red belongs to rank 5 but the dc tag is 0.

Am I missing something here? It seems like this part of the assembly was used to create the graph but when mapped back, the coverage (dc) is 0.

I might be misunderstanding something here but I would appreciate any thoughts about this.

Thank you!