Extension working only for some records and not for others

Welcome to the community, @Praveen_Jain! :grinning_face_with_big_eyes: Would you mind sharing the script that you’re using? It’s tough to know what’s happening without seeing the script details. When sharing the script, please format the code using the preformatted text option in the comment editor toolbar (the button looks like this: </>)

Thanks Justin for replying
Below is the code. I hope I have use the correct preformat for code.

let mainTable = base.getTable("Txn");
let mainTableRecords = await mainTable.selectRecordsAsync({fields:["MapIdentifier"]});

let lookupTable = base.getTable("Typ_Act_Map");
let lookupRangeRecords = await lookupTable.selectRecordsAsync({fields:["MapID","AccountsID"]});

for (let record of mainTableRecords.records) {
    let lookupValue = record.getCellValue("MapIdentifier");

    for(let rangeRecord of lookupRangeRecords.records) {
        if (rangeRecord.getCellValue("MapID") === lookupValue) {
            let linkID = rangeRecord.id;

            mainTable.updateRecordAsync(record, {
                "SuggestedID_Lkp_Ref": [{id: linkID}]
            });
        }
    }
}

Thank you so much. await keyword helps and I am able to get the desired results for all the records now.
I am new to scripting and still learning
Will learn how to build and index