Receivable data access set does not secure business unit

Summary

Trying to secure BU transactions using data access set does not work 19B

Content

Hello all,  We are on 19B and going live in 3 weeks with receivables we have 3 business units across 3 different ledger and using data access set to secure data. We have transactions in those business units.

I am trying to understand if someone had this issue: when we are connecting with a user that have access to ONLY 1 business unit (through data access set). This user is viewing all data of all business units which is wrong? Any ideas? We have opened a SR as we have tested many things and it seems not to work but it  actually works in Payable