Strange, I have this (same?) bug now in Automated v 4.8.6 but with a slightly different error message:
Template result: The block number 3 stopped the generation
Note: draft and private posts could be visible when creating the template, but cannot be used or included in the generated newsletter.
Also with the monthly newsletter sent today, the images extracted form every item are wrong, they are from (older) different topics. They were correct in the newsletter sent last month (october 2)