The way space-time works in this comic makes it entirely possible.
For them to be interacting with prescratch trolls right now only makes complete sense (And the "cheering" thing fits in to that perfectly) so I just assumed that's what it was.
tbh I pretty much feel like it's a Sorry I Thought That Was Obvious sort of thing given everything that was said (cheering, 4 universe instances, they're having a game of sburb, switching to kid guardian's game, etc)