Rumors of Nanase on Patreon (I originally forgot to make this public. My apologies to anyone who saw this early enough to be affected.)
Frequent rumors of Ellen and Grace being together made Nanase irrationally jealous.
Not of people thinking Ellen and Grace were together, but that there weren't a bunch of rumors about her dating someone.
The relatively rational response to dealing with this irrational desire would have been to be more obvious with her girlfriend, Ellen, or even to hug Grace more. Neither would have objected to either option.
Nanase, however, opted to use her magic to change her hair, then use her "Fox" spell to make a magic copy of herself with different hair, and hoped rumors would spread of her with Fox.
The thing was, there actually were rumors about Nanase. Lots of rumors. Those rumors had to do with her being able to use magic. Something about Moperville made most people not question this, but this did not mean it was never talked about.
Those rumors rarely got back to Nanase herself as people knew better than to speak of them with anyone close to Nanase nearby. This meant her usual informant, Justin, was rarely aware of them.
The majority of people who saw Nanase with herself correctly concluded that the green-haired Nanase was some of magic puppet. This was a case of many guessing correctly after witnessing Nanase's terrible acting, but it was also a case of Nanase not being as stealthy as she thought she was while using her magic.
And yes, Nanase did have a spell that could sense how many people were looking at her at any given time, and yes, she did fail to use that spell. Plenty of people simply saw her change her hair and summon Fox.
Many wanted to openly ask Nanase about Fox, but no one dared, and all discussion was made in secret.
After not hearing of any new rumors about her, and being rightly criticized by her friends for so openly using magic, Nanase soon stopped trying to get rumors started about her and Fox.
It would be a long time before she learned of the rumors that actually started as a result of her efforts, at which point her embarrassment was immeasurable.