It is still giving me an error when the text is > than 12 characters long and the sentance is (when printed through the loop) "You notice a wall of text in twitch chat and your hand instinctively goes to the mouse.", which is the first line in the paragraph. I found that even when you take out the range the same error occurs.
The bug may be in how you are storing your sentences, make sure you print out the sentences as you store them instead of when you retrieve them, hopefully, that'll help you find the issue. If not, let me know if I can help!