Thomas' last name, Norstein, being misspelled 'Nordstein' in the final episode may seem like a production error, until you realize that given where he studied and the general sound of his name, people in-universe might think that 'Nordstein' may genuinely be how it's spelled, like the confusion regarding Jesse Andersen's last name. note the d in the scandinavian word for North is silent. It wasn't as though he could correct them on the mistake, or even would care to at the time.
Mixed with Fridge Horror: Yggdrasil's extreme actions become much more understandable once you realize since the Digital World is for all intents and purposes his body, Kurata might well have caused injuries analogous to brain-damage.
Now we have Savers, which seems to go back to basics with just the partners evolving right? After all, after having the kids become Digimon, where else can they go? How about having the humans knock out Digimon without their partners at all. Masaru (and more to the point his dad, who could fight Ultimate/Megas level Digimon to a standstill) actually represent the next logical step, while at the same time, allowing Savers to go back to basics with normal evolution. Genius.
The absence of the Royal Knights could be construed as a sign of Savers having an Idiot Plot. Or it could be construed as them being occupied in alternate universes at the time. After all, Crusadermon's and Dynasmon's antics likely aren't appreciated by the other eleven.
Why didn't Ikuto's Digivice break when he Digivolved Falcomon to Ravemon for the first time, unlike the other three? Because he's emotionally more stable than them when he did that.