Is there any unexpected milter-greylist log entry in your syslog? How is it looking your INPUT_MAIL_FILTER definitions in your .mc file? Not only for the milter-greylist, but for other milters. Some milter may say "accept" instead of "continue" before the dacl stage of milter-greylist got called.
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RE: [milter-greylist] Can't get dacls to work at all
2015-12-01 by Bruncsak, Attila