I suggest to check the INI settings in the administration interface. For both frontend and backend they should be the same. Check also which template is used for rendering output. Compare the one from frontend with the one from backend (turn on 'List used templates'). There might be some difference.
I'm using ezoe v.5.1.0, and the solution given here doesn't work for me when I just press shift + enter several times. I need to write a space on every empty lines to make it work.
It seems logical because the settings concerns spaces and not lines, but you don't mention we need to put a space.
Is it the case and you forgot to say it ? Or is it supposed working without spaces ?