Ever since AutoSave was developed, and added to posts being edited, people have been having problems when editing un published posts. We see periodic cries of anguish, in Blogger Help Forum: Get Help with an Issue . I had been working on this post, for weeks! Just as I selected a portion to delete, AutoSave kicked in, highlighted the whole post, and saved an empty post!! and I was working on this post, along with another member of the team. We keep making changes, and erasing each others changes!!! Blogger allows long period editing of un published posts - and they provide team blog ownership - but you'll do better to not use either possibility, with any important projects.
What Blogger won't tell you