Some context when the exception is thrown. (Downloading Polish PKP Set 2.0.11)

The exact error message:

Unhandled exception at 0x00007FF84AF7AFEC (ucrtbased.dll) in openttd.exe: 
An invalid parameter was passed to a function that considers invalid parameters fatal.

I too have this issue. It also happens for me when I make a screenshot.

It only happens when I build a version myself; it does not happen with official binaries.

In VSCode, you have to hit "Ignore" first to get the debugger to tell you where it failed.

Error with whole map screenshot:

Exception has occurred: W32/0xC0000409
Unhandled exception at 0x00007FF9AF3CB7EC (ucrtbased.dll) in openttd.exe: An invalid parameter was passed to a function that considers invalid parameters fatal.

at screenshot.cpp, line 388. 387 is calling png_write_row.

I switched from x64-windows to x64-windows-static (like the official binaries use) and this seems to have solved the issue. I wonder if there's some core DLL mismatch happening with the shared versions.

https://docs.microsoft.com/en-us/cpp/build/reference/md-mt-ld-use-run-time-library?view=msvc-160

string(REPLACE "/MD" "/MT" ${MSVC_FLAGS} "${${MSVC_FLAGS}}")

This line in CompileFlags.cmake is forcing use of the static LIBCMT[D] lib.
If the vcpkg dependencies are built as shared libraries, then they link with MSVCRT instead, causing the conflict.

This problem doesn't occur with the official binaries because they are built with static dependencies.

I would expect a warning about conflicts though, as you get when you DON'T use /MT when compiling against static libs...

I guess it should be possible to analyse vcpkg triplets to determine compile flag.