Is it normal to have grad student instructors for upper division classes?
US News and World Report has data from 697 ranked colleges. Of these:

544 schools (78%) reported that no graduate students were the primary instructor of any course. These include all except two &quot;National Liberal Arts Colleges.&quot;
The 10 schools with the most graduate students as primary instructor were all large public research universities. These 10 schools reported that 18-26% of their TA appointments were as the &quot;primary instructor.&quot;

Purdue University is listed as the school with the highest fraction of graduate students as instructors of record. Their policy allows the department to assign courses to graduate students; it makes no reference to upper division or lower division.
As another case study, the University of California reports that &quot;as students progress through their academic careers and enroll in upper-division and graduate classes, they receive more consistent exposure to full-time permanent faculty and smaller classes.&quot; More specifically, the policy at Berkeley allows graduate students to teach lower-division classes, but they do so under the supervision of a faculty member, who remains instructor of record. However, Berkeley does allow graduate students to be the instructor of record for an upper-division course, though usually in exceptional circumstances only.
Summary: about 80% of universities do not allow graduate students to be the instructor at all. Of the other 20%, most are large public research universities. There is less data about the courses to which these graduate instructors are assigned, but Berkeley is an example of one school that will &quot;formally&quot; assigns graduate students to upper-division courses but not lower-division courses.