Honestly might be looking too much into it. They don't have really bad blood that we know of, so it might just be a case of them both having really busy schedules and it being too complicated of a process to get him over there to record.
Pokemon Scarlet
www.twitch.tv
In other news Julian's doing another Digimon stream on Twitch right now, and Ding Dong is actually on this time (maybe he was on some previous ones but I didn't see them). Haven't listened for the whole stream but he seems to be doing well. Aside from going on a brief tangent about lost media and something about Adult Swim it feels like he's gotten better since the big stream months ago, a lot of them just kinda joking around and having fun. Feels like the time away has done good for him.