Also, I’m annoyed that Dan Da Dan employs the usual miscommunication / misunderstanding trope. Momo could have hear Okarun out and avoid this needless conflict.

Yeah, that bothered me a lot too. "Let me explain." "No, I'm just going to keep believing the wrong thing." The only saving grace was that Okarun WAS wrong in that he lied to Momo about doing a report. It's not much but at least Momo getting upset isn't entirely unprovoked.