Feeds does not schedule a job with job_scheduler unless the import form is submitted

It looks like simply updating the form configuration is not good enough, you have to actually submit the import form before the new changes are persisted (in drupal 7 the lines where the magic happens are ~114 in feeds.pages.inc).

This seems to be a problematic interaction, as the following (confusing) cases can occur:

1. Set up a feed with no periodic import.
2. Do an initial import
3. Update the "frequency" setting to be every 1 hour.
4. (missing expectations): no periodic imports happen.

OR

1. Set up a feed to have an import every hour
2. Do an initial import.
3. Realize that every hour is hammering a server, reduce to every 24 hours.
4. (missing expectations): imports still happen every hour.