We've just upgraded from WeBWorK 2.13 to 2.16 on AWS, using a custom AMI derived from Amazon Linux 2. We use the math4 theme, without customizations. On the library browser page (and probably other pages), the page template tries to include the following non-existent files:
This generates multiple 404 errors on page load. I looked at the theme files and I see that are references to these files in the various .template files, and that they're wrapped in "#if exists" blocks. I'm unfamiliar with how WeBWorK theming works, but it seems like our platform is missing some library or utility that handles this pre-processing, or it's not working right. Any assistance would be appreciated.