I think some people misunderstood their relationship so much, usually teenagers tease and make fun of the people they usually have crush on. I myself have done that and people who had crush on me have also done that, it just shows that they are close enough to understand the jokes and find it cute instead of taking it negatively.
Because many people misinterpreted their friendship, causing them to distance themselves, although, in this era of bit me, I think the sunki is coming back T-T