Rmarkdown not rendering the specified output when knitting (but ok on build)

I have a project that compiles an Rmarkdown website. Within this project, I have a Rmd file that should output to a revealjs presentation, but instead the output when I knit is the website template. If I build instead of knit, the resulting html file for the presentation Rmd looks correct, but only if I build. I'd much rather knit to see the slides and then build when I am finished and ready to push the files to Github and serve them as a website.

I think this might be a very localized issue. Any tips for troubleshooting would be appreciated. Here is the link to the repo.. And here is the link to the Rmd file that should output to a revealjs presentation. You can see here that it renders fine when I build the site, just not when I knit this specific Rmd file in RStudio.

When I knit, I get:

I moved a few files in the repo in the course of my work today so it won't be possible to reproduce the problem. Still open to any ideas for how to troubleshoot this problem.