The Data Clock capability in ArcGIS Pro currently will not label the outer ring of the Data Clock. For example, the data I have in the attachment below is from 2005 and 2006. The inner ring (2005) is labeled, but the outer ring (2006) is not. I've tested multiple times with different data sets and contacted technical help, who also confirmed that the outer ring currently cannot be labeled. The Data Clock is a wonderful tool, and I would love if it could have full labeling capability for the outer ring of data.