Field Integrity Exception comes when you have space between your transaction line items.
If you have a large number of records in QuickBooks, then it will throw this error while syncing and it can block the sync as it will identify the line space as a new item you have added which does not have a Name or Quantity. It will quit the sync and there is a chance of missing transaction on the other side if you did not check the records in Salesforce.
Field Integrity Exception comes when you have space between your transaction line items.
If you have a large number of records in QuickBooks, then it will throw this error while syncing and it can block the sync as it will identify the line space as a new item you have added which does not have a Name or Quantity. It will quit the sync and there is a chance of missing transaction on the other side if you did not check the records in Salesforce.