@Kenneth12
It is hard to tell from your pictures but as I look at them again, yes I agree with you, both the visible broken joints do not relate to the positioning of a hardwood joist underneath.
In my country that would only be done as the work of some 'handyman' who is not aware of building regulations and is trying to cut a corner or two with construction costs. If local authorities here saw something like that they would condem the structure until the entire flooring was brought up to a safe code standard.
I understand this is in Germany Kenneth, and not wishing to be uncharitable to the German people, I would think that much of Germany after the last major conflict would not have been rebuilt according to building codes and proper safe practices. If would have been rebuilt out of sheer neccessity to get people housed again, and many buildings would not satisfy construction safety codes such as exist in the US and here in Aust.
So for that reason it would probably not be seen as a building issue because it would be so common, and it would be seen more as a 'user' issue.
I might be wrong, just my feeling on it!
Hope your flight home was a good one Ken.
Cheers.....Rob