If an app you’d installed added a new configuration setting, editing that installation’s settings could silently drop whatever you typed into the new field. The form appeared to save normally, but the value reverted to its default the next time you loaded the page, since the installation had never stored a value for that setting before and the save request quietly matched nothing.
This is now fixed: values you enter for a newly added setting save correctly, whether the installation has been running for years or you just connected it.
We also hardened the settings page itself, so an installation with no saved settings at all no longer risks showing a broken page instead of a working form.