The 周 (circumference) kanji is on Level 14. But you learn the radical 周 on level 7, and use this radical in kanji such as 週 (week) and 調 (investigate) on level 7 as well. I found this quite odd and even a little confusing- anyone have the same problem, or is this just a nitpick from my end?
Without looking at it very closely, my immediate intuition is that it is probably placed at level 14 because the most common vocabulary terms using it would require kanji from the higher levels whereas the earlier levels with kanji that use it as a radical could match up more evenly with the vocabulary available at earlier levels
調べる is an extremely common word, it’s probably why it’s taught early. 週 will also come up a lot, perhaps disproportionately so in beginner material that often discusses time.
周 is certainly not rare either, but maybe a bit more abstract.
I object to some of WaniKani’s shenanigans with the way radicals are handled but in this case it’s taught with the same meaning as the kanji, so I don’t find it particularly confusing.
下 comes up in level 59 
下 is a different situation, where they reintroduce a radical long after the stand-alone kanji has been learned.
That would be one of the “shenanigans” I object to.
So you’re happy for 下 to shenan the one time, but having it shenan again is beyond the pale?