@raj_nann, I think I know what you are seeing. As @Joe91 wrote, Manager breaks the production order into multiple transactions when there is insufficient stock on hand. The first uses up all available stock at the current average price. It is shown with the production order reference number, if there is one. Subsequently, additional entries are generated automatically as more stock becomes available. These temporarily drive the quantity on hand into negative territory. The reason this is necessary is because, after the available stock is used, there is no average cost to apply to the Inventory - cost account when the finished goods produced with the backordered green caps are eventually sold. These automatic entries do not show the production order reference number.
When you next buy the back-ordered item, a new average cost calculation was started and carried forward. The dates on the automatic entries are changed to the date of the new purchase. Had you looked at the item transactions on 5/9/2019, and in isolation, you would have seen a negative balance of -46650.
In your particular case, however, when you purchased 140,000 on 6/9/2019, you also entered another production order that used 126,250 green caps. Apparently, you did not put a reference number on that production order, but it is the one with “ER120” in the
Description column. This production order took precedence, leaving only 13,750 green caps to be applied to production order #12. So the quantity on the automatic entry from production order #12 was adjusted by Manager. A second automatic entry (for a total of three) was created for production order #12, with 32,900 pieces.
Then, on 7/9/2019, you bought two large lots of green caps. So the remaining 32,900 green caps from production order #12 could finally be priced. The date for the last automatic entry was adjusted again.
In summary, back-orders produce what may be confusing quantity balances after the fact, because their application dates shift as purchases are made. This confusion can be made worse because of the precedence Manager assigns to transactions entered for the same dates. But, once purchases catch up with production orders, the balances are correct. I assume that if you had counted your green caps on the morning of 10/9/2019, you would have had 290,500 in stock.
As a final note, the situation could be even more confusing if there are multiple production orders using back-ordered inventory. But eventually, everything will settle out.