Clark, Allana, and Tess all had different ways of reacting to Kon's apparent return from the dead. So did Connor. Where the others were demanding his time and attention, Connor was...not ignoring him, per se. He just wasn't falling all over himself to be around him. And it wasn't Kon's fault, but Connor had, honestly, been through a lot recently. Kon's death reminded him far too much of losing Cutter. No, he hadn't been there when it had happened, but he had spent plenty of time by his friend's side, feeling completely useless for what he hadn't done.
There was also a lot of guilt there. If he hadn't listened to his instinct, if he had just gone with Tess' plan, maybe they wouldn't be in this mess at all. Maybe they'd have sent Clark's alternate back weaker and damaged but in one piece and they'd have their Clark back now and Kon, too. But they couldn't have known. They didn't know how the switches worked, if it was just their minds or also their bodies, and then what?
Topped with guilt over his fight with Kimberly and the fact that he'd all but retreated into himself over the last week, and Connor didn't really think he'd be very good company for Kon to begin with, let alone when it was really the first time he'd seen his friend since his 'death'. And there they'd be doing exactly what they should have done that night.
And yet, he showed up in the lobby, fedora perched on his head and hands jammed into the pockets of his denims, looking a little tired and a little less excited than usual, but still there. "Hi," he offered, as soon as he saw the younger man. He looked fine. But that didn't mean anything. And that scared him.