[Plugin: Feedwordpress] Memory Error using Cron Link

I am having an issue with updating a Feedwordpress feed. If I update it manually through the admin interface, it works fine. However, if I use the “secret” URL that can be used with cron jobs, I consistently get a memory error thrown by class-simplepie.php. I’ve tried to trace this by adding in various debug statements, but it looks like each method is doing the same thing…I can’t figure out why one process is using so much more memory that the other. Any ideas?