outlook 2011 marks IMAP emails as READ soon after they are received, even though I didnt read them

I have a 2 gmail accounts configured as IMAP on outlook.

Each time I receive an email on these accounts, it will appear as UNREAD for a short while, then, after a couple of syncs, it will turn to READ, even if I do not read it, hover over it, click on it, etc...

I thought that could be a sync problem with my iphone (the same accounts are also configured as IMAP on my iphone) so I switched off the iphone. Same problem
I thought that could be a sync problem with the web interface of gmail so I logged off my accounts on my firefox web browser and exited the browser. Same problem.

I have no other device that connects to my gmail accounts neither in pop nor IMAP.

I have a third email account configured on outlook as pop, and this one works perfectly.

The problem happens on outlook for mac 2011 version 14.3.5 and 14.3.6 (just updated outlook to that version).

I am on MAC OS 10.6.8

This has been happening since I decided to use IMAP for my gmail accounts (I was using pop before).

It is very annoying as I regularly miss time critical emails.

Anyone who can point me to a solution or a work around will have my eternal gratitude!!

THanks :)