This “infinite restoring database” problem still seems to persist in 4.13 and I’ve encountered it now in multiple installations on several service providers. The thing is, when it gets stuck at this point I always see two things:
1. All the themes, content, plugins etc. seem to have been transferred succesfully
2. You get logged out from the importing installation
I’m starting to think this problem has something to do with point number 2. I’ve checked and I don’t get an error.log so could it merely be you get logged out of a session while the final stages are going on and the plugin has no way to handle that?