Deleted photos occurred when using "write metadata to file"

Hi, I am a casual user of PSE 15 and have recently migrated my catalog to a newer Win 10 laptop. Everything seemed to go well.  Today I was browsing my photos and remembered about manually saving metadata so I started the process and then went to lunch.  When I returned the process was finished an all appeared well.  An hour or so later I opened the recycle bin just to see if I could save some room and there were over 650 photos in there, all with the deleted date/time corresponding to when I saved the metadata!  I was panicked, but when I reopened PSE all the photos still appeared to be there.  I was still not comfortable so I tried to restore the photos but windows said all the photos already existed in the folders and did I want to overwrite them?  What happened?  The deleted photos appear to be duplicates but why are they there?

Thanks for your help,

Ken

PS:my catalog is still on the original computer in it's entirety so I have not lost anything permanently.