I think he personally liked to keep his physical affection with HC private. This can be exemplified by moments some fans have seen & even included in some (rare) contents. For e.g., did u know that during GliMo recording (for their byl comeback), fans saw RJ backhugged HC behind the curtain only because the stage was lighted up. Also, even during the crazy era that was hot sauce, in that Studio Choom behind; when RJ initiated the hug, I don't think he noticed they were being recorded, more so, since other dreamies were kinda in the same space as well. He might not cling to HC per se, but he gravitates towards him a lot. And lately, I also think it maybe because he is fulfilling his role as the nurturer in Dream that you see him freely hugged other Dreamies more. I believe it was his way of supporting the Dreamies. If u noticed, JM has been acting the same as way; always giving all the members warm hugs. That being said, i think RJ do treat HC similarly as the rest of the dreamies. But rather than hugs, we see him act more subtle. If u look at it, RJ has been checking up on him a lot, asking if he was fine, & responding to his comments plenty