Teacher 2 tries to change the teacher's material - Unexpected Behaviour

[Tatyana-Kravchenko]

Teacher created course (course id: {{courseIdForMaterials}})
POST {{host}}/api/v1/courses
Request Body
{
"title": "How to create test cases1 {{coursePostfix}}",
"description": "Basic course about test design technique",
"visible": true,
"categoryId": {{categoryIdForMaterial}}
}
Teacher added a material in this course
POST {{host}}/api/v1/courses/{{courseIdForMaterials}}/materials
{
"title": "Additional material {{materialPostfix}}",
"data": "stringstri",
"order": 2
}
Id the created material was saved in environment {{MaterialIdTeacher}}

Teacher 2 tries to change the teacher's material
PATCH {{host}}/api/v1/courses/{{CourseIdForChangingTeacher}}/materials
Request Body
{
"id": {{MaterialIdTeacher}},
"title": "New title {{coursePostfix}}",
"data": "Test Design techniques 12345",
"order": 2
}
Tests:
pm.test("Status code is 403", function () {
pm.response.to.have.status(403);
});

pm.test("Response time is less than 1000ms", function () {
pm.expect(pm.response.responseTime).to.be.below(1000);
});
pm.test("Error message is correct", function () {
const body = pm.response.json()
pm.expect(body.errors).to.equal("You're not owner of this material, you can't change/remove it")
});
Actual behavior

1. Status code is 200
2. Response time is less than 1000ms
3. Expected behavior
4. Teacher 2 changed the teacher's material

Expected behaviour

1. Statuse code is 403
2. Response time is less than 1000ms
3. The text error message ("You're not owner of this material, you can't change/remove it") is correct
4. Teacher 2 doesn't manage to change the teacher's material
   Screenshots
   If applicable, add screenshots to help explain your problem.