I got issue at magento 2 development env after updated magento npm package (quite outdated)
Not sure this problem from magento or grunt less

https://github.com/magento/magento2/blob/2.4-develop/package.json.sample
Updated dependencies to
grunt 1.4.1
grunt-contrib-less used v3.0.0
Internal magento not use less latest version
I got issue at magento 2 development env after updated magento npm package (quite outdated)
Not sure this problem from magento or grunt less
https://github.com/magento/magento2/blob/2.4-develop/package.json.sample
Updated dependencies to
grunt 1.4.1
grunt-contrib-less used v3.0.0
Internal magento not use less latest version