So I played some more today and in level CHILL-11, I might have found a bug. I don't have a screenshot of before, but in the end, the vertical word "MASS" had two different characters at the end first (I remember, because I tried all combinations ending in the two characters in a brute force way, nothing worked). The horizontal word that lines up with the first "S" in "MASS" ended up being "TSME", which I don't think is a word, and it might have been "TAME" or something before the word "MASS" overwrote the second letter.