The date is stored as the serial number and can be many different formats in Excel. When merging with the text directly, the date will become a serial number.
To avoid turning dates to serial numbers, when merging with text, you can use the TEXT function to convert the date to text format. Here are some examples.
1. August 11, 2013 (MMMM DD, YYYY)
=TEXT(A2,"MMMM DD, YYYY")
2. Aug 11, 2013 (MMM DD, YYYY)
=TEXT(A2,"MMM DD, YYYY")
3. 8/11/2013 (M/D/YYYY)
=TEXT(A2,"M/D/YYYY")
4. 8-11-2013 (M-D-YYYY)
=TEXT(A2,"M-D-YYYY")
