I just noticed this after we got back from the rally.(Murphy’s law) Our main slide out topper is separating at the top back. Has any one had this happen? Any suggestions?

You saying the hardware is separating from the side of the RV or stitching of the fabric?

The stitching is separating from the side

Then you have 2 options,
#1 remove the fabric & have it restitched at an uhpolstery shop
#2 remove the old & replace with new for about $100.
With a couple sets of hands neither is a difficult job. There's several utube videos of how to.