Here's something that's not clear: since it isn't a novel and, in fact, a life she lived previously, how does she know what happens to Lucas in her absence??
I just read from the raws, and I'll make it short based on my assumptions :
Original Judith following the OG story > Judith got regression and the regression Judith is Korean Judith
.
Meanwhile for Luca..
Luca OG actually reached the mature age but the following story is tragic so he made a wish to regressed > he regressed (so he knows how to read and matured), but kinda shocked with Korean Judith behaviours, because she seems different from the OG story
For someone who is a victim of rumors, she sure is quick to believe them