We have a project in Captivate 2019 that after answering the knowledge check the slide won't advance. We've checked the timeline and it hasn't elongated. The student clicks anywhere on the slide but the slide just sits there.
The default setup of a KC slide is with Infinite Attempts, which means that the slide will only advance when a correct answer is given. There is no Last Attempt event in that case. Please check the actions in the Quiz Properties.
Have a look at this blog where I explain differences between KC slides and normal quiz slides:
I'm pretty sure when the developer was testing the project he'd selected the correct answer but it still wouldn't advance.
You need to show us screenshots of the Property settings for the KC slide.
What is the Success action?
Can you post a screenshot including the quiz panel? Without knowing all the settings we are just guessing as to what the problem might be.