Okay so hear me out..... A lot of people are saying minjae is a red flag like the manipula...

Minjae in side stories which is not part of the main plot, creates fake situations where he tries to make Heechan feel special, anxious cause he thinks it's unlikely for Heechan to continue relationship with him naturally as Heechan had poor example of love (his father).

I can't guarantee 100% cause MTL is a bit confusing from time to time.