Using Variables and Triggers in a knowledge check with a result slide not working

It's hard to troubleshoot without seeing the file. The triggers look okay, so my best guess is that the Slide Layer Properties don't have "Reset to initial state" for "When revisiting." 

Here's the User Guide info about adjusting Slide Layer Properties: Slide Layers in Storyline 360 - E-Learning Heroes (articulate.com) 

If the progress layer uses "Reset to initial state," then I suggest you upload a copy of the .story file. Here are the best practices for uploading a .story file:

• Only include slides that are involved in the problem.
• Be sure all objects, layers, motion paths, and variables have meaningful names.
• If there is proprietary content, replace or delete it. For example, replace proprietary text with ipsum lorem text.