Reformatting numbers permanently rounds them?

Using Excel 2013. I have received some sizeable workbooks from somebody else, and I went through and reformatted the numbers to my own liking. One of the columns contained 8-digit decimals. I reformatted the column to two decimals and all the numbers automatically got rounded to two decimals - I've never had this happen before. Is there some option or formatting setting that caused this?:

Thanks - that's the culprit. Need to be careful when working on someone else's workbook!