Large feed folder not automatically updating

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I have "Tools -> Options -> Feeds -> Automatically update the feeds every x" set to 10 minutes, but my YouTube feeds are not automatically updating.

Updates on startup do work and other feed folders also update as expected. I don't have any folder-specific settings so it should also not conflict there.
I have 215 feeds in this folder, is there some kind of limit for it to update automatically?

Manual updates also work as intended.