When using the /give command and targeting multiple players, the string commands.give.success.multiple should be displayed. Instead, commands.give.success.single is displayed, with the first placeholder (playername) used by number of players who were given the item.
net.minecraft.server.commands.GiveCommand#giveItem
if (collection.size() == 1) {
cn2.sendSuccess(new TranslatableComponent("commands.give.success.single", n2, eh2.createItemStack(n2, false).getDisplayName(), collection.iterator().next().getDisplayName()), true);
} else {
cn2.sendSuccess(new TranslatableComponent("commands.give.success.single", n2, eh2.createItemStack(n2, false).getDisplayName(), collection.size()), true);
}
Can confirm for 1.17.1