@HazeLNuts thank you for your help.
only the two bigger ones in the back had the problem, but the one in the back left didn't looked that bad and recovered already after 2 days from it, no signs there now.
but the one on the back right, which i posted the pictures of, still got the problem. in the beginning the leaves were completely yellow with dark veins, but now the green comes back. only on the newer top leaves, the lower leaves looked fine. the two ladies in the front no problems at all.
i wonted to flip on monday already but then noticed the problem so i thought i should wait. sadly they get way too tall now and i really need ro flip them or i will get big (like really) problems, but if you say i should wait till monday or tuesday i will do so, otherwise i would have done the flip tomorrow already.