Hi @Madhu1 - welcome to the Community!
Based on what you have shown as the expressions used to calculated your values, you’re getting into an issue with memory addressing. The Array.reduce() function works on the array directly, so the concurrent executions of reduce() on the same array can yield unpredictable results (as you have seen). Try the following:
[].concat($orderLineItems).reduce((acc,curr)=> acc+curr.totalItemQuantity,0)
[].concat($orderLineItems).reduce((acc,curr)=> acc+(curr.itemDenomination*curr.totalItemQuantity),0)
This should resolve the issue you are experiencing by first copying the array into a new memory address before performing the reduce() method.
