[Bug]: Applications seems to crash due to loss of connection to the CSS file

Component

UI (ui.*)

Severity

P0 - Critical (crash/unusable)

Shiny Version

1.5.0

Python Version

3.13.7

Minimal Reproducible Example

Any example goes, as long as you use a .css

Behavior

My application written in Shiny is deployed on a server. The code on this server serves multiple dashboards. Basically, I start the same application with different configuration files and they all run with uvicorn on a different port. Caddy is in front of it to do proxying.

The source code of the dashboards is located on a network file share. Basically it is for access rights that we put it in each department's data directories.

All works, however, from time to time the application "crashes" and shows a hideous screen. We only see the 2 svg files of our icons. The rest is gone. When I go into the developer tools of Edge or Chrome, I can see it seems it has lost the connection to the .css file.

There is no way to recover from this. We must stop the uvicorn project and then it works again. We can assume there is a temporary glitch to file server, but the uptime of that thing is 99.99-percentish.

Error Messages (if any)

Environment

Windows 10/11
Any browser (we use Edge and Chrome)

The report names no source file, test, or entry point. Start by reproducing the intermittent missing-CSS state with a Shiny app using a .css, then inspect browser asset requests and the uvicorn/Caddy path while considering the network file share; done means the failure is isolated and the application no longer becomes unusable.