Emails showing different subject to mail headers

Question

My mail provider is gmail via IMAP, and I connect to this via the mail application.
Until recently all was good with the world.
Now I randomly get a mismatch between the mail sender, the subject that is listed for the mail and the actual email that is shown.
To give an example. if I received two emails from the same person within a few hours, the first email would have the correct sender but either the wrong subject or email body or both and the second email would have the reverse. So the only part that mail is getting right is the sender, the rest is mismatched.
When I look in more details at the email headers via > Mail>View>Message>All Headers the correct Subject is listed in the headers but a combination of the wrong subject appearing in the preview and the wrong actual email are the manifestation of the problem.
Some additional info.
In Mail, I have multiple folders, and total mail volume is plus 6GB.
What have I done up till now to fix the problem
1. Mailbox rebuild; done multiple times, and whilst this does fix the problem for a short time, within 24 hours it reoccurs with different messages (random). Problem with this fix is its temporary and rebuilding your  mailbox multiple times is a pain.
2. Removal of account from Mail and rebuild. again this is a temporary fix and whislt this does fix the problem for a short time, within 24 hours it reoccurs with different messages (again random).
3. Total removal of the mail account from mail and deletion of all the associated mail files in the ~/Library/<user>/Maildata/V2.... folder followed by a full import of the mail from scratch. This one is a bit more interesting. The occurrence of the problem seems to be on the newest mail. With this method all mail rules/filters had also been deleted before the resync of mail, hence ruling out the filters as a possible source of the issue. But again randomly mail would be incorrectly listed with the wrong subject.
Why is this a pain, I'll add this just to get everything down on this listing.
So an email client that get one third of the tasks it meant to handle isn't really an email client at all, its a mail transformer and not in a good way, more of a random deceptacon kind of way and its highly infuriating. I have seen various listings about similar problems to this but mostly they seem to be solved by mailbox rebuilding of the mail indexes etc etc. These aren't permanent fixes for this problem and I would be very interested to hear if anyone has similar and has actually fixed this, or are people simply waiting for a fix in the next upgrade of mail in yosemite? or is these something more going on between mail and the interaction with gmail?
Comments welcome.

Answer 1

Kfir,
I guess you've implemented a mapping to create the target email ? If so, you could a feature to build the subject depending on a source message context (field value ? sender ? etc) ...
Otherwise, you may play with dir objects (intf determination for instance) to use different mappings (so diff. subjects) to create target mail (depending on sender/receiver etc) ...
Rgds
Chris