Why So Many Digests?

Hello Hashcat Folks,

I have a WPA/WPA2 hash I'm running dictionary+rule attack on.
I converted the .cap file I had to the .hccapx format needed for hashcat.
The attack is running just fine, but was just curious about this bit:

Why does it show 0/21 digests? I understand that the hash has been salted once (0/1); but shouldn't there only be one possible digest from the hash?

If I understand it correctly, the digest is just the output of the hash?

Thanks.