Adobe Firefly

Hi @FLRSH Collective Studios 
Firefly in its current version (Image 3) is not good at inserting text into the image. Say you have the prompt below:
Create a book cover with the title "Book about Firefly".
Firefly won't fully understand what is the text to insert and how to do it accurately. Sometimes you will get text that looks close to the words you have requested but with some garbled characters. Often, you will get odd looking characters like you have experienced.

I think people have requested Firefly improve to allow text inserting.

For your case, I'd suggest you get the book cover without the text, then use Photoshop to insert the text (providing you have Photoshop or something similar).