.Hello Enrico Bossart,
This is indeed strange behavior, for example in mendix 10.19 it does not show this behavior.
I also do not see currently any known limitations for 10.22 and 10.23 regarding this issue.
However, I see that there were some issues related to mappings in version 10.22, the best you can do now is to file a ticket to mendix.
Hope this helps,
Good luck!
10.23 still the same behavior