[Bug]: Data conversion using foreach seems to cause data loss

[janihur]

Description

I'm converting data from list of records to table of records with foreach and add(). When printing the source and target data structures it looks like data is lost during the conversion. E.g:

Source data:

{"number":739,"coords":[{"x":0,"y":41},{"x":1,"y":41},{"x":2,"y":41}]}

Actual target data:

{"coord":{"x":0,"y":41},"number":739}
{"coord":{"x":1,"y":41},"number":739}

Expected target data:

{"coord":{"x":0,"y":41},"number":739}
{"coord":{"x":1,"y":41},"number":739}
{"coord":{"x":2,"y":41},"number":739}

This is just one example. You'll see other examples when checking "y":41.
The compiler reports no errors/warnings.

Steps to Reproduce

$ bal run main2.bal > output
Compiling source
        main2.bal

Running executable

$ ack 739 output
{"number":739,"coords":[{"x":0,"y":41},{"x":1,"y":41},{"x":2,"y":41}]}
processing 739
processing 739 coordinate: {"x":0,"y":41}
processing 739 coordinate: {"x":1,"y":41}
processing 739 coordinate: {"x":2,"y":41}
{"coord":{"x":0,"y":41},"number":739}
{"coord":{"x":1,"y":41},"number":739}

The conversion code:

public function main() {
    EngineSchematic engineSchematic = data();

    foreach PartNumber partNumber in engineSchematic.partNumbers {
        io:println(partNumber);
    }

    // 739 is just one example of lost data
    // e.g. check also other coordinates where y = 41
    table<PartNumberTable> key(coord) partNumbers = table key(coord) [];
    foreach PartNumber partNumber in engineSchematic.partNumbers {
        if partNumber.number == 739 {
            io:println("processing 739");
        }
        foreach Coord coord in partNumber.coords {
            if partNumber.number == 739 {
                io:println("processing 739 coordinate: ", coord);
            }
            partNumbers.add({
                coord: coord.cloneReadOnly(),
                number: partNumber.number
            });
        }
    }

    foreach PartNumberTable partNumber in partNumbers {
        io:println(partNumber);
    }
}

The complete source code and output attached.
bug.zip

Affected Version(s)

$ bal version
Ballerina 2201.8.3 (Swan Lake Update 8)
Language specification 2023R1
Update Tool 1.4.2

OS, DB, other environment details and versions

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 22.04.3 LTS
Release:        22.04
Codename:       jammy

Related area

-> Compilation

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[nipunayf]

The above issue is produced since the hash-collided keys are not handled in the TableIterator, and the bug is fixed with: #41722