Niai says 苺 is not in WK, when trying to add it to another kanji's page

[lunacodes]

When I try to add 苺 (Lvl 14 - Strawberry) to the list of similar kanji on another kanji's page, it says "Not in WK!" and won't let me add it to the page. I've tried this on multiple different kanji pages. I've also confirmed that I can add other kanji just fine. This one just seems to be missing for some reason.