Addendum:
About a week after this review was online, I got a little Päkchen. This is new slides (free) and the following text were:
"... Unfortunately we noticed that despite the steady control of our own quality assurance several films sets have fallen in the shipping, which due to an incorrectly adjusted laser may be defective. Since we can not exclude at this stage that you affected are, we will send you here a defect-free set of ordered films with us as free replacement. A return of the films have already been delivered is of course not necessary.
For possibly inconvenience and apologize ... "
Unfortunately I can not test whether it would actually work, as I have already applied another slide. But for this service, there are two other stars from me. Nowadays, not only the product counts as such, but also the corresponding service. If I ever need to replace my now-adhesive films, I will do so with the newly supplied and then, if necessary, enhance the review continues.