This is a known problem, common, with WordPress, to the issue in the future posts, never fixed since version 2.6.0.
The Core Team seems to ignore or underestimate this problem for a long time.
It is certainly not my fault or responsibility.
It is certainly not the fault or responsibility of this plugin.
We should thank those who dedicate their free time to develop plugins useful, and give the opportunity to present their own problems ...
Your case is the most classic of all:
1 - Have you planned a week ago a post.
2 - WordPress has not published.
3 - The post has been marked as Missed Schedule.
4 - After a week we're aware of this problem.
5 - After some research have found and installed WP Missed Schedule.
6 - After a minute since it was installed the plugin has performed its function perfectly, releasing Missed Scheduled Future Post.
The fact that the date of Missed Scheduled Future Posts is the original scheduled, and not the current released, is absolutely correct: it is a post a week ago and not a minute ago.
This is a limitation of the API inside of WordPress related to this mechanism, explained in the FAQ and in the Changelog of this plugin.
Only the Core Team can correct ... it is useless to blame this plugin (even with nik and at different times) or its author.
If you have installed this plugin a week ago, you would not have had this problem.
This plugin was immediately resolved after one minute this problem!
But I tried, and I'm trying to develop a version of WP Missed Schedule that try to correct this problem: install this version ... and let me know about it.
With the greatest respect: Best Regards :)
P.S. Please : read here ...