When one changes the environment on a host, and these do not have the same classess (name) one can not submit the changes to the host. Instead the site loads back into the host edit screen without a visual indicator which tab generated the error , like when one has a duplicate IP address the network tab lights red. However foreman does indicate the error when one clickt the classes tab and actually lists the wrongly configured classes. I assume this is just a visual bug and not a functional bug due to the error being displayed once one finds the faulty tab.