Unable to place buildings because of negative population

This is related to todays balancing changes: https://innogam.es/Hero24Changes  

The original bugreport was: My population is suddenly negative, I can't place more buildings requiring population.
This indeed is not a bug, because of the balancing changes.
However, not being able to remove buildings that require population or placing ones that provide it is a whole different story. There is another bugreport for that, that will be forwarded.