Earlier today we were having problems creating a new site and using Blog Templates support to clone a "template" site. The problem was that it wasn't using the theme of the "template", it was defaulting to the 2015 theme.
Anyway, in an attempt to fix this I installed 3 new updates to WPMUDEV plugins, Blog Template, WPMU Dashboard and the Prosites plugin.
Now when we create a site from template the site gets created correctly but we are getting this error from prosites:
Here is a full video walk through of reproducing this: