I just tried to scan 3 notes, EUR 5, £10 and $20.Its not a myth - but it seems you have a scanner that doesnt have the chip. Every paper note in the world has a particular pattern of dots made into the design. For euro its the little circles - the scanner looks for that pattern and refuses to scan when it detects it. I tried.
neither scan was complete, with only about 10 -20% of each note scanning.