Looking at the changelog, there have been more than 70 versions of Lodash in less than four years. The first was in April 2012. [1]
_.padleft
So in less than a year "padleft" came and went away because all strings don't start on the left and someone decided that "left" means "start" except that the reason that it doesn't is the reason that it was changed. Even worse, the 4.0 documentation does not document that _.padstart renamed _.padleft. It's hard to grok what cannot be grepped.
Why blame someone for depending on padleft in a world where libraries swap out abstractions in less than a year? Breaking changes are bad for other people. Semantic versioning doesn't change that.