On the advanced features page, there's a 'progress-tracked roles' option; this controls who appears on the completion progress report.
1) the advanced features page should only have on/off features, not settings for those features, so this should not be on the page
2) it would be better if this uses the same setting as gradebook as it wants the same thing, basically 'who should be considered as a student'
Current solution is to change this to use the intersection of:
b) gradebookroles setting
In long term might be better to change how gradebook does this as well (eg capability + enrolment)