notify sometimes sends empty emails

I am often receiving empty emails from the notify.module at drop.org. By empty, I mean that they have the busual header/footer but no content.

My configuration is a bit unusual. I chose to receive new comments and nothing else. If this configuration is unsuported, we probably shouldn't offer it.

Here is a recent email:
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Greetings weitzman,

Recent content
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This is an automatic mail from drop.org
To stop receiving these mails go to http://www.drop.org/