TL;DR: We just fixed a bug in the system that was preventing some items from unlocking. They’re either already in your queue, or will show up in the next few hours.
The Whole Story
We are quietly working on some data tracking improvements in WaniKani, and have been for several months. One of the new things we’re tracking is when you unlock a particular item. “Unlocking” happens when you meet the requirements for an item: when you level up or when you get all the prerequisite items to guru (ie. the radicals for a kanji).
For a while, we thought we were tracking this properly, but, well, we weren’t. We didn’t catch the inconsistency until we started using the unlock time to determine what appeared in people’s lesson queues. After some very rapid feedback from everyone, we fixed the bug causing the inconsistency and fixed up the missing data—or so we thought.
We only touched the records we thought were affected. It turns out, we were a little too narrow in our search for inconsistent data, and we left some lessons locked, even though the prerequisites for those lessons where met.
So, we’re at it again. This time, we are double checking the unlock dates for everything and setting them to the correct time if they’re missing. Setting that date unlocks the item, so those updated items will show up in your lesson queue. The server is grinding away at all those calculations, and should be done with them later this evening (PDT).
We’re sorry for the errors on this one, and for the frustration or confusion for those folks with incorrectly locked lessons. We’re striving to make the Crabigator faster and stronger—thanks for sticking with us!
PS. To all the devs out there, we have a ton of automated testing in place. Clearly, we missed some scenarios in there, and we are continuing to add more tests to the suite to catch stuff like this.
Yep, 4 new lessons appeared and I was completely unaware of all that stuff going on in the background, so
edit: though in my case I realized I just just guru-ed the stuff leading up to those 4 lessons, so the whole substance of my reply boils down to “SECOND!”
i know the feels; i got 100 new items instead of the usual 70 when i leveled up. of course, being the masochist that i am, i went and did all 100 lessons because why not.
Why I wasn’t affected. Well, you’ve fixed it, that’s good! Don’t mind for a few new lessons, even though those old lessons are still there. I’m very carefully track what is going on in my queue, as I’m waiting to get to lvl 10 asap . Phew. So far so good, btw. Everything’s working.
After days of wondering why I have unlocked kanjis when all radicals are guru’d, I thought this would be the explanation: a glitch, a minor bug. But now those kanjis are still locked. Are you still going through the system to unlock everything? I am just wondering. Maybe I am doing it wrong. Do you not unlock kanjis by guru’ing radicals?
it really helps.
Well, you’ve fixed it, that’s good! Don’t mind for a few new lessons, even though those old lessons are still there. I’m very carefully track what is going on in my queue, as I’m waiting to get to lvl 10 asap 
. Phew. So far so good, btw. Everything’s working.