Question with adding tooltip to each of the ID in a text string of ID

Hi everyone, 

My read-only grid has a column storing a text string of IDs, which looks like this 001/002/003/004/005/006, and it was queried from record type 01

I want to add the tooltip, which will show the Client category of each of the ID in the list, the information is stored in record type 02, and I use the ID from record type 01 as reference data to query. So within richTextDisplayField, I set the tooltip parameter like below: 

tooltip: a!forEach(
                    items: split(
                                fv!row[recordType!record01.Id,
                                 "/"
                             ),
                    expression: "Category:" & 
                                a!queryRecordType(
                                        recordType: recordType!record02,
                                        fields: recordType!record02.clientCategory,
                                        filters: a!queryFilter(
                                                        field: 'recordType!record02.Id,
                                                        operator: "=",
                                                         value: tointeger(fv!item)
                                                         ),
                                        pagingInfo: a!pagingInfo(1,1)
                                 ).data[recordType!record02.clientCategory] 
                  )

I expect that when I click each ID, the tooltip will show: Category: Abcdef, instead I got something like this photo:

I think it's the forEach () issue, but no idea why it's the issue... Anyone know what the reason is?