Are the commercial transactions carried out by vendors who reduce the quantity of goods (such as reducing the number of paper boxes or the weight of canned goods) while keeping the agreed-upon price fixed considered to be among the divinely prohibited acts of short-weighing or short-measuring?

The sale mentioned is considered a 'programmatic sale' (بيع البرنامج), which is permissible according to the Maliki school if the item sold matches the described specifications. However, what the seller does by cheating and deceiving is forbidden by Islamic law, based on the Prophet's (peace be upon him) saying: "Whoever cheats us is not of us." And the perpetrator falls under the threat of the verse: "Woe to those who give less in measure." The seller guarantees the resulting deficiency and is obliged to deliver it to the buyer. The buyer has the option to uphold the sale or to annul it.