You certainly do something wrong:
Uups! I didn’t read correctly. Sorry for that! You are right:
If you modify text size in Rollover State, this new size is applied to the other breakpoints as well. This clearly is a bug!
Here a video demonstrating this::
I reported this in the Prerelease Forum.
A possible workaround:
- Go to the second breakpoint and copy the menu.
- Rightclick onto the menu and choose "Hide in Breakpoint"
- Then, paste the menu "in place" again, rightclick onto it and choose "Hide in other Breakpoints".