I had the same issue and just resolved it.

The key is to click in the text in Excel. I found this behaviour in text cells that had a line break in them. For example, imagine the quotation marks in the following do not exist:

"Text like this will not produce quotation marks"

"Text like this WILL produce quotation marks
"

To remedy this place your cursor on the line break in Excel and press delete to eliminate it. Both the quotation marks and line break in Word will disappear on next update.