No deployment or log errors, but most javascript and css files are not being served

All javascript and css are within R packages (like shiny, shinydashboard, and so on). These are not custom files.
The app runs fine locally on Windows.
The start up logs are identical between and the local app.
I've compared installed.packages() between shinyapps and local (and local renv.lock) and they all match.
The app webpage in source form is nearly the same apart from some extra javascript and css.
Yet, when checked in Chrome developer tool most files other than images aren't being downloaded.

The shot below are captured in Chrome's developer tool. Only the first 3 CSS files have actually been served. All rest are reporting as 4.6kB and are actually showing a html file previewed in the next shot.

Has anyone experienced this before?
Anything else I should check?

I'm on a free account using a 1GB large machine. I've set startup timeout to 300secs (max) and no difference from default.
I've run, managed, and deployed apps to Shiny Server Pro, and RStudio Connect servers before. And deployed to other platforms also. This is the first time I've tried a large app on shinyapps though.
Small test apps work fine but they don't include much more that the "shiny" package.


  • completely reworking the project's renv environment from scratch,

  • including updating to latest releases of all required packages, and

  • removing one unused package dependency

the app now loads and runs without any glitches.