On the Kanji learning screen for 誕 the tab that shows the words it’s used in shows お誕生日おめでとう。The とう part is outside of the red bounding box and on the line below in white and barely visible.
What device are you using?
I had the same problem in reviews, the string is just way too long. You can see it wrapping even on desktop if you reduce the window size a bit.
** it’s the only instance in the first 30 levels I can remember
I’m on a desktop PC.