In bridge 126.96.36.1992
Duplicates of files are randomly displayed in the main window and are counted as different files.
Browsing previews by means of previewing full screen leaves on exit TWO selected files instead of just the last viewed one.
The mentioned issue is fixed in the latest patch release #188.8.131.523, Please install and confirm if that fixes the issue.
You can refer the issues fixed in the patch @ https://helpx.adobe.com/bridge/kb/fixed-issues.html