More attributes are selected by themselves upon saving

I have a weird problem with Woocommerce for days now that i havent been able to solve or found a similar problem/solution by someone else in the forums.

I have my “Size” attribute wich i use for my products and each time i create a new product and select it, by entering its terms (in my case european shoes sizes 38,39,40 etc)and saving as draft or publishing woocommerce adds more by its self! Some times one, sometimes more.

For example: I select the Size attribute, selecting the terms 38,39,40 and i press Save as Draft. When i go back at the Attributes panel, the attribute Size will have the values 38,39,40,41.

I know it may sound silly but i cant figure out why this is happening. I have tried reinstalling woocommerce with no success, anyone know what im doing wrong?

Thanks in advance.

http://wordpress.org/extend/plugins/woocommerce/