Google Docs question
 

I created a spreadsheet and sent it to a colleague, who added data and shared it with me. Now I can read the updated sheet but when he opens the original email (the only one in the thread), only the original data I entered is there. Why can't he see the updated document?

Sounds like he may have created a new version - it's the "and shared it with me" language that makes me suspect this is the case.

For the workflow to happen the way you're expecting, he would have opened the version you sent the link to, added content and then just closed the document. There's no re-sharing required.

Do you see two separate versions of the document in your Google Drive?