If using cmder do use a custom shell executable to run tasks else you might find source file not found issue.
"windows": {
"options": {
"shell": {
"executable": "cmd.exe",
"args": [
"/d", "/c", "[cmder_root]\\vendor\\init.bat", "&&"
]
}
}
}
Above resolves the issue. Refer to the link for more details. cmderdev/cmder#1985