@atiq The point of my suggestion was to try to break-up the SET command and the webpack command into two commands.
On *nix it’s possible to do NODE_ENV="production" npx webpack --progress --colors and the scope for the variable is set for the current execution.
set sets an environment variable on the Windows command line, but it essentially consumes the whole line, so SET NODE_ENV="production" webpack --progress --colors actually sets the environment variable NODE_ENV to the weird value "production" webpack --progress --colors. The && is a meta character for the command line that should actually split the line into two commands.
Avoiding these kinds of issues are why I advised these three solutions earlier.