Reproduced in Master: 3c86f9d39dbb813de43ae4034d4571e04f38701b
Reproduced in Branch: b2c9911e713b1aa0f2238b932d7684c8346a4e1b
Steps to reproduce:
1. Add new site
2. Enable local live staging
3. Add a number of pages with child pages.
4. Publish a few of the pages and their child pages.
5. Publish a different set of pages and the child pages.
When publishing the set of pages, not only do you have to select all the pages you want to publish, but you must de-select the previous pages.
You should only have to select the pages you wish to publish.