Originally planned for May of 2019, its release was postponed. This delay was announced in a teaser published on May 31, 2019, La Maison LOONA, which previewed 3 songs. On May 30th, LOONA's producer Jaden Jeong posted on his Instagram the same message in "La Maison LOONA" teaser: "Delayed but Someday".
- one way and Where you at were supposed to be part of it, according to the songs' album descriptions.
- From one way's song description in beauty&thebeat: "LOONA The Ballad [...] is an album composed of ballad songs with the best melodies among many common ballad numbers. 'one way' is a sneak preview for what is to come, through the emotional expressions in the voices of LOONA/yyxy."
- Snippets of "Daydream" and "Stay With Me" Babe were hidden tracks on physical versions of [X X].
- The teaser "La Maison LOONA" ("The House/Home LOONA") used pictures from the photoshoot of [+ +].
- "Daydream", the "Crystal Ballad", is a LOONA 1/3 type of ballad, music style wise.
- "Stay With Me Babe" , the "Hyper Ballad", is a ODD EYE CIRCLE type of ballad, music style wise.
- The third song previewed in "La Maison LOONA" teaser, the "Bliss Ballad", is a yyxy type of ballad, music style wise. Its melody is reminiscent of "one way".
- ↑ Instagram: Jaden Jeong May 30, 2019
- ↑ MTV: Jaden Jeong made you stan LOONA, and now he'll do the same with OnlyOneOf