From what I remember reading back then was that they were facing some post-production challenges and were needing some extra time to polish up the VFX for the drama. I'd assume it was probably the visual effects for the gumiho parts that needed extra work
SBS has updated their show description on their site:
This gumiho is not the kind of gumiho you’re used to.
“If I had just one more day! I could have become human! How unjust!” The weeping gumiho from Korean Ghost Stories, desperate to become human, has grown cliché through endless remakes. We’ve already had the “girlfriend gumiho,” the “boyfriend gumiho”—so why another gumiho drama? Because the gumiho in this drama is completely different from the one you know. She doesn’t seduce men and rip out their livers to become human— in fact, she lives anxiously, keeping good deeds at arm’s length and men even farther away, worried she might accidentally become human.
A quirky MZ-generation gumiho who enjoys eternal youth and beauty, refuses to grow up, takes responsibility for nothing, and cherry-picks only the fun parts of the human world as if she’s playing a game. Huh? But as we talk about her— doesn’t this gumiho somehow resemble today’s youth more than any other drama protagonist?
The heart of a gumiho who wants to stay a child forever. Some may criticize her as immature or irresponsible, but many young people today will feel that somehow, she’s just like them. They’ll hope she continues to live freely, joyfully, and happily, and cheer her on.
And so, this drama will become a supportive anthem that empathizes with, comforts, and encourages the youth of this era.
1 
1 
1 
http://yoonmediagroup.com/bbs/board.php?bo_table=sponsored&wr_id=118
https://www.youtube.com/watch?v=a5PJfT8MAqs
https://www.youtube.com/watch?v=ahPQntMcxAA
https://www.youtube.com/watch?v=dD-viBP3PA4
https://www.youtube.com/watch?v=jyx4mXNrYkA
https://x.com/studiodragonKR/status/2001200819920863483
https://x.com/KBS_drama/status/2000702411992916068
https://www.youtube.com/watch?v=XtLoSclacF4
https://x.com/CJnDrama/status/2001427188042829999
https://x.com/DisneyPlusKR/status/2001427436777406732
https://www.youtube.com/watch?v=F9SZf_QxfeA
https://www.filmmakers.co.kr/proCrewRecruiting/27104225
https://x.com/gibaekkkk/status/2000116522140987840
This gumiho is not the kind of gumiho you’re used to.
“If I had just one more day! I could have become human! How unjust!” The weeping gumiho from Korean Ghost Stories, desperate to become human, has grown cliché through endless remakes. We’ve already had the “girlfriend gumiho,” the “boyfriend gumiho”—so why another gumiho drama? Because the gumiho in this drama is completely different from the one you know. She doesn’t seduce men and rip out their livers to become human— in fact, she lives anxiously, keeping good deeds at arm’s length and men even farther away, worried she might accidentally become human.
A quirky MZ-generation gumiho who enjoys eternal youth and beauty, refuses to grow up, takes responsibility for nothing, and cherry-picks only the fun parts of the human world as if she’s playing a game. Huh? But as we talk about her— doesn’t this gumiho somehow resemble today’s youth more than any other drama protagonist?
The heart of a gumiho who wants to stay a child forever. Some may criticize her as immature or irresponsible, but many young people today will feel that somehow, she’s just like them. They’ll hope she continues to live freely, joyfully, and happily, and cheer her on.
And so, this drama will become a supportive anthem that empathizes with, comforts, and encourages the youth of this era.
https://programs.sbs.co.kr/drama/humanfromtoday/about/84578