On January 11, shortly before episode 15 of JTBC's 'SKY Castle' aired its weekly broadcast, an online post containing alleged spoiler content of the drama's upcoming storyline went viral, garnering the attention of many drama-watchers. 

The spoilers spread quickly online via SNS portals and went as far as to trend #1 on various search engines with the title, "'SKY Castle' Spoiler". Then, after episode 15's broadcast, viewers noticed that some events predicted in the spoiler content actually happened in episode 15.

However, the online spoilers released on January 11 also contained shockingly unexpected predictions for the remainder of the drama including tragedies for most of the characters, and some onlookers felt that the online post seemed too detailed to be simply "fan predictions". Others even commented, "Did the drama staff spoil it on purpose?", "I saw some online evidence of real script-like images", "This doesn't seem like a fan wrote it at all", and more. 

As the issue grew, JTBC's side stepped up with, "It's not true that our broadcast contents were spoiled online. From our perspective, we feel that viewers wrote various predictions about the drama, and some predictions coincided with the actual storyline, which made onlookers feel as if the online posts were real spoilers." JTBC then added in regard to the potentially shocking contents of the drama's upcoming episodes, "Please watch the broadcasts." 

Meanwhile, episode 15 of 'SKY Castle' once again recorded an all-time high in viewership ratings, with an average rating of 16.4%. This is once again the highest ever drama rating for any JTBC drama, and a huge jump from episode 1, which started at 1.7%. 

Currently, 'SKY Castle' has 5 episodes remaining until the end.