Batch Number Selection in Sales Order Screen

Dear Friends,

I've tried to allocate a specific batch through the Batch Number Selection Screen while being in the Sales Order. It has selected the relevant batch and updated the available qty.

While opening another Sales Order for the same Item and trying to allocate/select the same batch , I've noticed that the available qty is unchanged and shows all the units in the stock.

I want to use this functionality to control batch number allocation during the sales process, in order not to sell twice the same batch to different customers.

Is that a "bug" or a "feature"?

Thanks in advance,

Simon