We upgraded a service from ASP.NET 8 to 10. No application code changed—but our Puppeteer-based document pipeline completely broke. The root cause wasn’t .NET. It was a subtle base image change: Debian → Ubuntu , which replaced a working Chromium install with a non-functional Snap wrapper inside Docker. The Setup Our document generation pipeline works like this: Render HTML using Puppeteer Use Chromium as the headless browser Post-process assets with Sharp Run everything inside a Docker container This setup worked reliably on ASP.NET 8. What Changed? As part of the upgrade: From: mcr.microsoft.com/dotnet/aspnet:8.0 (Debian-based) To: mcr.microsoft.com/dotnet/aspnet:10.0 (Ubuntu-based) At first glance, nothing looked risky. But this OS-level change had a critical side effect. The Real Problem (Root Cause) On Debian: apt install chromium installs a real Chromium binary On Ubuntu: apt install chromium installs a Snap wrapper, not the browser itself That distinction is the entire problem.…