REST API Search with property is not working properly

Hello ,

Our vault has a class called "MCA". MCA objects has Documents in it. I want to get object IDs of documents of a given MCA. (I am trying to download the files)

When I examine the Document objects I can see that those documents' class is "MCA" and has a property called "Scale calibration" and  scale calibration property value is the name of it's parent MCA. So to get the document objects of a given MCA, all I have to do is filter by object type = 0 (because they are files) and by property value of "Scale calibration".

I got the ID of the "Scale calibration" property by using this endpoint -  /REST/structure/properties

"ID": 1529,
"Name": "Scale Calibration",


And I am using this endpoint and query parameters to filter the document objects of  MCA = R320 - 3789803 - 26317 
- /REST/objects?o=0&p1529=R320%20-%203789803%20-%2026317

I assume the returns objects' "Scale calibration" property should always be "R320 - 3789803 - 26317". But the response includes objects, that does not even have a value for the "Scale calibration" property. And the response does not contains the actual file objects in MCA = "R320 - 3789803 - 26317".

Could anyone help me with this? What am I doing wrong in here?