node-reinstall looks for curl https://raw.githubusercontent.com/creationix/nvm/ where nvm project page now shows curl -o- https://raw.githubusercontent.com/creationix/nvm/ (note the extra "-o-").
As a result the parsing fails silently and the hardcoded fallback version is used (#46).
A possible more future-proof solution would be to parse nvm's package.json (https://github.com/creationix/nvm/blob/master/package.json) rather than the project page.