OS X 10.10.5 (14F1713) Kernel Version:Darwin 14.5.0
I have consulted all the above. The messages have not been read on any other device, nor have they been flagged by the mail server (fastmail). A couple of examples:
(1) Messages from mailer@doodle.com are consistently flagged as junk, yet the log says “matched rule <From (address) Is Equal to “mailer@doodle.com”> in SpamSieve whitelist”
(2) Messages from ebay@ebay.com are consistently flagged as junk, yet the log says “matched rule <From (address) Is Equal to “ebay@ebay.com”> in SpamSieve whitelist”