A lot of feeds not getting processed on schedule


I have a multisite which uses Autoblog to push feeds to a lot of sites (around 150 sites/feeds).

A lot of the feeds miss their scheduled times (all are set to update daily). Maybe 20% of them get updated as they should, the rest miss their time and get highlighted red in the feeds list.

It works if I do a manual update for all, but the scheduling seems broken.

What to do?