Bug: save printing several copies doesn't work anymore

WINDOWS version of Firefox!!! Until the last update, we were able to set through the printer settings (in "system preferences -> printers" of Windows 10), how many copies should be printed each time the print dialog opens. Since the last update, Firefox always wants to print just 1 copy. If you choose 2, he prints 2 this time, but this setting is neither saved nor does Firefox read the seting from the printer settings in system preferences. If the print dialogue opens, it wants to print only 1 copy, no matter what you've chosen before. So you have to choose it each time the printer dialogue appears. Silent printing with 2 copies isn't possible any more. But it's very important for our clients as we have a cash register system running through Firefox. Please fix this ASAP!!!