Is SFA always trying to match (ISIRs) on middle name

We do not have middle name (or middle initial) in any of our ISIR matching criteria combinations in our SCHOOL workbook. When trying to load 2027 ISIRs, we have several who should have matched. We're using SSN/last name/first name/DOB as our first combo, and all of these data points on the ISIR matched what we have in SFA for these students. We have matched previous year ISIRs for them with this information. But for 26-27 ISIRs are not matching.

I took two of these students, mocked up ISIR files so that the middle names matched what we have in SFA for them. These records loaded. The only thing I changed on these were the middle names and the transaction numbers.