hi big fan of your work. i've played since version 0.5 but as i've brought my saves forwards i've lost the Samga and Faye endurance modes despite never actually failing/attempting them.
Viewing post in SpunkStock: Music Festival v0.12 Demo comments
the "X" signifies that they are not available (Samga and Faye simply do not have Endurance modes in the current version). There is nothing to worry about. You haven't lost anything.
Side note: There are no plans to have any content that you can "miss". You will always be able to go back and get all the content.