Type-based slicing on MedicationActivitiy has never quite seemed to work. I tested a MedicationActivity missing the IVL_TS effectiveTime, and it did not throw an error. Additionally, I tested PIVL_TS and EIVL_TS effectiveTimes missing the operator attribute, and they did not throw an error either.

It seems that slicing GTS elements by type:$this does not seem to work.

Ideally this can be solved in the publisher. If not, an alternative may be to slice on the existence and value of the operator attribute (and then set operator to 0..0 on the IVL_TS slice).