Changes in Card Style are not saved when configuring GreenHooper Project Templates

When changing the project template in "Administration > GreenHopper > Project Template", it's written in red letters that 'All changes will be saved automatically'. But when the "Card Style" is modified in the project template, this change is not persist.

When accessing the GH boards, it's like the changes are discarded.

However, changes made in "GH > Tools > Configuration" appear to be saved.