Hello!
Welcome to the forums
In year 12, your assignments need to follow the rules set out by the
syllabus for that subject, which is prepared by QCAA. Before an assignment is used for your class, your teacher is required to submit it to QCAA for endorsement by their assessors. After the assessment has been used, a sample of student responses is sent to QCAA so they can check that the assessment was marked correctly.
This should mean that any dodginess from your school is caught out.
Now looking specifically at health assessments, what you've described seems like a modified version of IA1: Investigation-action research. You can find information about this on page 48 of the health syllabus, but essentially it's researching an issue and designing an action plan in relation to a local or regional community context. If you would like to see sample assessments for IA1 you can find them
hereTLDR; Nothing seems dodgy here and QCAA has a process for catching dodgy assessments.
Hope this helps! Please let me know if you have any more questions