Progress by Pressing Enter - Skips over layer

I've designed a module with two quizzes that have to be accessible to students who use a mouse or a keyboard.

Originally, the first quiz was set up so that students would click on a selection and then click Submit.  This functioned properly.

However, when I tried to add an additional trigger to allow students to press Enter in order to submit the interaction, I encountered some problems.  The correct or incorrect layer would appear for a brief second and then the slide would jump to the first slide in the activity without being prompted.  

I've tried creating a duplicate slide (1.28 K-1) that only uses triggers which require the student to press Enter (thinking that perhaps the Click triggers and Press Enter triggers were conflicting) but I'm still encountering the same issue.

I've attached the file to this post.  The quiz I'm referring to is: Name the Study Strategy and have been trying to get slide 1.28 K-1 (newly added with Press Enter triggers) or 1.27 M-1 (original in quiz series with Click Triggers) to work.