I also encounter this problem for many times, but i can not fix it. This problem result from the line spacing when you copy the graph into word document. Please do the following:

1. Select the text and the graph and then right click and chose "Paragraph"
2. In "indents and spacing" tap and under "Spacing" and under "line spacing" click drop down arrow and chose "single". This bug should be away.

Hope this instruction would be a help.