I can confirm I also have the same problem with the Zeiss Touit 50 macro on my Sony a6000 - I am not happy.
Given the length of time it has taken Zeiss to produce this lens it is unacceptable that such a simple flaw was not detected.
Believe it or not, my Nex5r was no longer functioning after using Touit 12. I have to send the body back. Having Sony made Zeiss lenses like 24-70 f4, 55f1.8, 35f2.8, I can say Sony makes much better Zeiss lens in terms of build quality and mechanical performance. I also happened to have 10-18f4 which is great in many ways.