Here's my hypothesis guys: I think Haein wouln't lose her memory but pretends to be, to catch SML off guard and claim back that slush fund and company back from those Mother-Son duo, and finally a happy ending.
I dont think she plagiarised this work, just think about it, in this world of internet those whose claim to be "original writer" could've made their work publish as webnovel or even webtoon before the airing of "k-drama" to prove their claim. BUT THEY DON'T.
I think Haein wouln't lose her memory but pretends to be, to catch SML off guard and claim back that slush fund and company back from those Mother-Son duo, and finally a happy ending.