Office 2013, skydrive and file dates in future

I bought recently Office 2013 for my company, and I got it together with SkyDrive storage space. I planned to use it in my comapny to share files between two employees. Everything works like a charm, but ... there is suynchronization issue I am fighting with. 

Reproduction steps are as follows:

1. User opens Excel file "file1" from SkyDrive, 

2. User clicks "save file as" and chooses different name for the file, for example "file2" and saves it on Skydrive in the same folder. 

3. User does some changes on the opened file2. 

4. User clicks "save". 

--- And here software gets crazy ---

Office Upload Center yells with red-cross icon that it failed to save the file because there is newer version on a server (there is synchronization conflict, however user 2 did nothing that time). When I select to let me choose which version of the file to take, it shows two files of the same name, but the one on server has modification date two hours forward, meaning in future!! My both users are working in the same timezone, and their machine clocks display pretty much the same time. This issue appears always, it is not intermittent. 

No signs of sync issues untill they "save file as", so regular saving and opening works as expected. Any help will be greatly appreciated. 

Regards,