TurnitinOC - 'Invalid JSON' response when using special characters

When attempting to view originality reports for sakai demo student student0008 (El Niño), or student0009 (Ângeolo Haslip), the following JSON is sent to TII:

{"similarity":{"modes":{"all_sources":true,"match_overview":true}},"viewer_default_permissions_set":"INSTRUCTOR","author_metadata_override":{"given_name":"
El","family_name":"Niño"},"viewer_user_id":"some uid","locale":"en"}

The response is a 400 with message "Invalid JSON".
Students without accent characters are fine.

Encode transmissions to TII in UTF-8