Thanks for the info
Sadly it was not well known to me and if I don't know why the bug occurs it is a bit hard to search for something, even if it is well documented.
Never stumbled uppon the building_present thing in the first place, because I did not use it with another building bonus...
Is there some thread where bugs like these are listed. All I know of is the Bugs and how to fix them list...
But maybe I am blind.
Anyway. Much thanks, this made some things really clear after a bit of an absence with modding