Barcode scanning missing letters

Hi, when i scan a barcode to firefox(console/input box...), it sometimes missing some letters(i think specially when it has double or triple identical letter like "000" in "asdasd000asdasd" become "00". I think the problem is when it scan really fast a string letter by letter because when i scan the barcode to text editor and copy-paste it it doesn't have this problem. the problem happens only on ubuntu firedox, on windows it works fine on the same device. another thing it that on stronger device it works fine on ubuntu firefox. i am using firefox latest version in all of my devices. thanks.