Try this: in RocketLauncher package, go to "Front Page" override, type something in Custom CSS box and click save. When the page comes back, it doesn't have the tick besides it. So, without changing anything click save again, and you'll lose the previously saved Custom CSS value.
I noticed this happens on text and textarea fields when they have no value in Default override, if a value have been set for them in Default override, the value does not get lost.
I think I've seen this problem on Assignments options before too, when by clicking 'save', the chosen assignments got lost, but I can't remember when that happened.
This has been tested in 1.23 and 1.22.