We have confirmed that with ES3. We dont have this issue with our old ES env.
I'm not sure whether it use to work earlier as well or not and neither anything about this mentioned in watched folder documents. But the fact is documents with future date in Watched Folder doesn't even work with ES4 as well. Why I'm doubtful about this feature because LiveCycle other components like Digital Signature or Reader Extensions doesn't support documents with future dates.
But anyways, I'll ask the concerned team to check it and then either fix it if it's a functionality break compare to previous ES env or update the documents accordingly.
We've logged an internal bug (3557368) against the concerned team to check this on priority.