Strange behavior of ObjDef().OccList() when working with a matrix. Looking for advice.

Dear colleagues, good afternoon.

I’m working with matrices in ARIS for the first time and would appreciate some advice. I have a “Positions – KPI” matrix.
I expected to traverse it in a script using the following chain:

var tmpDef = objOcc.ObjDef(); // get object definition from its occurrence on matrix 
var tmpCnxs = tmpDef.CxnListFilter(Constants.EDGES_IN, 100); // get all connections from object definition on matrix 
for (var i = 0; i < tmpCnxs.length; i++) {
   
var tmpSourceDef = tmpCnxs[i].SourceObjDef(); // get source for each connection definition on matrix. This is KPI object
   
var tmpOccList = tmpSourceDef.OccList(); // try to get list of occurrences of this definition. But it doesn't work!

..............
}


And the problem happens at the last step: .OccList() returns an empty array. An empty array exactly, with no error message at all. But this object definition does have occurrences — at least one on the matrix itself and another one on an FAD model.
So array length should be not 0, but 2. This approach works perfectly on other model types. However, on a matrix I only get an array with length 0.

Could you please advise what I am doing wrong?
Thank you in advance for your help.

Best regards,
Anton