Yes and no, relationship stays on 20 and then later on 40, as Yuna expects you to do something specific for her (your character says something like "I feel like my relationship isn't progressing, I need to talk with her about it" which is a hint for you to go to her at night and chat with her (living room -> give gift -> chat) she will tell you what you need to do in order to progress)
Suspicion also plays an important role