business data object getting set with empty values

I have a form with 10 fields which gets opened up when I click “Run” in Studio (Bonita 7.2.0). A user fills this form and submits. When I see the form in form editor, the “value” field carries values like “formInput.applicantBdmInput.firstName”, “formInput.applicantBdmInput.lastName” etc.

After submit, it goes to 1st approver which is supposed to view the form in read-only mode (same fields but read-only). Since this approver needs to only put his/her comments and set approval status, so he has two additional fields “status” dropdown and “remarks” text field shown on screen in editable mode. 1st approver decides to approve a request and puts in remarks (optional) and submits the form. Note that in the contract of approver1 step, the BDM is selected completely with all fields. But in the “Operations”, I have kept only two line items. One to update “status” and another to hold the “remarks”. Since other fields are read-only and are not required to change, so I removed all other operations. Note that to show the initial data to approver, I have declared a variable on approver’s form to hold business variable as

Name: request
Type: ExternalAPI
Value: …/{{context.applicantBdm_ref.link}}

I use code like “request.firstName”, request.lastName", “request.age” etc as “value” of fields to show the values filled by the request initiator. So far so good. No issues. Values displayed, forms get submitted by 1st approver successfully.

Now the issue comes when 2nd level approver who has same set of fields from same BDM with same two additional fields “status” dropdown and “remarks” text field to update case at his level.

This 2nd approver leaves some field’s data as it is and in some he changes data. For this step, the contract in studio has same BDM and this time, I did not remove any operation line item from “operations” in studio because I want the values in BDM to get updated with form field values. After correction of data in fields, when 2nd approver submits the form but the fields shown on third step to a third approver are blank.

These last two lines in above description mentions about my actual problem. Everything is auto-generated everywhere except the change of “value” field content using form editor from “formInput.applicantBdmInput.firstName” to “request.firstName” in 1st approver step. Similarly 2nd approver is also shown filled values using this code.

It seems that the values from the form page shown in browser itself is coming as blank and when operations are hit as part of step chain, the empty values from form gets updated into BDM and thus no data is shown to third approver.

Can someone help me in resolving this error?