Can only move to the next slide when on a quiz slide!

You're up against the built-in functionality of the "Submit Interaction [question]" trigger. 

• If the question provides immediate feedback, the trigger scores the question and shows the appropriate layer (e.g., Correct or Incorrect).
• If the question doesn't provide immediate feedback, the trigger scores the question and jumps to the next slide. 

Here's one way to work around that:

• Add a blank slide immediately after the freeform question, so it's the "next slide."
• Put a trigger on that slide that jumps to the desired slide when the timeline starts.
• If you're using the built-in Menu, be sure to remove the blank slides from that. 

Another option: provide immediate feedback. Then adjust the "jump to" triggers on the Continue buttons on the Correct and Incorrect layers.