It seems that when you choose the moderator group, if a user belongs to multiple groups CB workflows will only query the lowest group ID.
Example:
User in group id 3 and id 5 with moderator set to id 5 in CB will only see "No Pending Actions" even if there are some. Even though the user belongs to group id 5, CB workflows only seems to recognize the first id group 3 (the way it is displayed in order in the user list in Joomla)
User in group id 3 and id 5 with moderator set to id 3 in CB will see any of the actions that need attention.
I am not sure if there is a work around for this other than reordering all the groups so that the moderator group for CB has a lower ID than any other group. This is a problem for me with a superadmin group that has a lower id than any other group.