Conclusion
As soon as I “touch” something in the non default language structure field (= default and non default are no longer the same) my structure stops working properly.
I really can’t find the problem.
Does anyone of you has an idea? I just found out that I have the same problem on two websites. I’m sure the oldest one didn’t have this problem earlier but I can’t remember if I upgraded the Kirby version.
This is standard behavior. As soon as there is a translation, further changes to this field are not reflected in other languages, because the field counts as one field and not every entry as a separate field.
I just didn’t think enough to the fact that, of course, it is just one field.
Thanks for telling me about blocks and layout fields so I won’t make the same mistake.