The expected behavior is that PeerMark grades are not passed back to the LMS grading area. This is because PeerMark assignments are treated as part of the main paper assignment, and the LMS grading area only pulls grades through from a paper assignment, not its parts.
Note: All PeerMark related grades will only be visible within Turnitin Feedback Studio when logging into the Turnitin website directly via turnitin.com / turnitinuk.com. However, we recommend always accessing Turnitin via your LMS - please only log in directly when absolutely necessary. Logging in via the Turnitin website may result in your access to your institution's Turnitin account being locked. Should this happen, it would require action from your Turnitin Administrator to manually unlock your account via the Turnitin website.