Ya, here's some examples of spam:
https://github.com/vuejs/vue/pull/11847/files
https://github.com/vuejs/vue/pull/11853/files
https://github.com/vuejs/vue/pull/11820/files
https://github.com/vuejs/vue/pull/11818/files
All within the last month.
Maybe there's some tutorial for 'how to submit a PR on GitHub' that links to Vue.js and people are following that?