Hey there, and welcome to Apple Support Communities, Duane Stevens!
From my understanding, it sounds like some of your audiobooks show the arrow indication you can skip forward or backwards by seconds, and other times it will send you to the next chapter.
Listen to audiobooks in Books on iPhone - Apple Support has some information regarding skipping forward and back, and how to change the number of seconds you want to advance. It’s important to note, that if you’re downloading audiobooks from an app outside of Apple Books, the options may differ.
If you’re using Apple Books specifically, you can remove the audiobook and download it again using the steps here: Read books and more with Apple Books - Apple Support I’d also recommend testing this on another device to see if the same thing occurs.
If the same thing occurs, I’d recommend that you Contact Apple Support.
I hope that helps, and thanks for using Apple Support Communities. Have a great day!