My issue is NOT with files created in the WSL filesystem, or with files created through WSL on the C: drive. The issue is with files created by Windows programs on the C: drive as seen from WSL. First, the contents of /etc/wsl.conf:

[automount] options = metadata,case=dir,umask=22,fmask=11,uid=1000,gid=1000

(Partial) results of mount -l:

C:\ on /mnt/c type drvfs (rw,noatime,uid=1000,gid=1000,umask=22,fmask=11,metadata,case=dir)

Again, no issues with files created from WSL:

cd /mnt/c touch test.txt ls -l test.txt

(Partial) output of last command:

-rw-r--r--

But when I create a file using a Windows application, like Notepad , WSL shows it has these permissions:

-rwxr--r--

There shouldn't be an executable bit set for the owner. I've tested this with multiple programs and in different directories.