"Good" mail going back to Spam folder after training

This just started yesterday (after about a month of use). Going through my Spam folder I occasionally find a valid message and train it as good. The message is moved to my inbox as expected.

On certain occasions now though, the trained message will remain in my inbox for a few seconds and then pop back into the spam folder. I have tried manually marking these oddballs as Not Junk, but that has no effect. The only thing that seems to work is to manually add the addresses to my whitelist.

Has anyone else experienced this?

Mac OS X Mavericks

Apple Mail will not re-apply the rules or re-filter messages automatically. So what you are seeing is probably because another computer is seeing the messages as new and applying its rules.

Please also see SpamSieve and Multiple Macs.