Text color and boldness changes randomly on my spreadsheet

Text color and boldness changes randomly on my spreadsheet

Suddenly my spreadsheet BOLDS random text in a lot of cells on the spreadsheet when only one cell is supposed to be bold.  It also randomly changes a lot of cell text color to red when maybe only 1-2 cells are supposed to be red.  This just started happening a day or so ago.  I will change it back and a minute later it's back to being bold and red again.  Any ideas what is causing this?