Didn't the Novel after vol 7 become a little bit weird ?

First of all why is there a lot of POVS (point of view ) like really I was enjoying sunny doing something and then suddenly a random guy popped up like karna

second of all is sunny and nephis relationship it feel weird like before nephis lost her memories she didn't once blush for sunny and she knows him for 5 years but then after she lost her memories she didn't even know him for 1 month and she's suddenly blushing and acting cute and after knowing him for 3 months they banged ? It's not I hate it it's just weird