Why can't IIS read Web.config within a folder created by Bash on Windows?

Credit to therealkenc at github.com/Microsoft/WSL/issues/3596 for pointing me in the right direction. The issue is related to Per-directory case sensitivity and WSL.

Query a directory's case sensitive flag:

fsutil.exe file queryCaseSensitiveInfo <path>

Set a directory's case sensitive flag:

fsutil.exe file setCaseSensitiveInfo <path> enable
fsutil.exe file setCaseSensitiveInfo <path> disable

After disabling the case sensitive flag on the WebBash directory, IIS read Web.config just fine. This led me to consider the possibility that IIS was looking for lower-case web.config. I re-enabled case sensitivity on directory WebBash and copied Web.config to web.config (yep, Windows Explorer let me keep both in the same folder). IIS read web.config just fine!