If you use the "Copy from all" functionality on sales quotation and copy from existing sales quotation lines then the system doesn't copy information of the RetailSalesQuotationLine like "Manual discount percent" and "Price locked".

At first, the new sales quotation line seems to be okay, but as soon as you trigger a recalculation the prices/discounts might change due to the not copied information.

Original Yammer thread (https://www.yammer.com/dynamicsaxfeedbackprograms/#/Threads/show?threadId=3187002764935168).