Germany 6pf Hitler Definitive With Printing Error On Cover?

Hello, I have found one Germany cover mailed in 1945 with 6Pf Hitler definitive pair and both stamps appear to have defect caused by production/ printing.
One stamp has white line all over the stamp and little bit diagonal line between two of them.
And bottom stamp has also white line in lower right corner.
Two pictures are posted below.

Does anyone know is this printing error or how to categorize it? If it is error then how common is it? Thank you for your help.

All the scratches extend into the margins, the top one even may continue to the left onto the cover.

I am not convinced it is a printing error. It appears like someone or someone has scratched the stamps.

It doesn´t look like scratching. I thought so too first. But white line on the top is not flat with paper (relief) and both lines don´t continue onto the cover (end on perforation). It appears to be caused during production

Production, likely. Printing error, no.