Online and Offline Sync issues

Hi Guys,

I am using both Zoho Docs online and Zoho plugin for MS Office.
Want I want to do is simple : My collaborators uses the online UI to make changes to xls file while I am reviewing and modify them directly in Office.

However it seems I have an issue between the online and offline edits.

If I open the local version and save it -> it gets synced to Zoho Docs and when my collaborators open it from the UI they get the last version. OK

However if they change the document through the UI, when I try to open it in Office via "From Zoho Docs" I get a warning message "you already have a local copy of this file. Do you want to overwrite?"
-> if I click on YES, then it opens the local file and I don't get the latest version
-> if I click on NO, nothing happens (I would expect it would open me the latest version from Zoho Docs but it does not).

Do I do something wrong or is it a bug ?

Thanks for fast answer,
Chris