For some reason Defender apparently hides quarantined files when the originating folder gets excluded. Experienced the same weird thing here when I checked the issue earlier.
Just reinstall vorpX, that will replace the file. If you didn’t keep the web installer, you can get a new one any time: https://www.vorpx.com/request-new-download/
This issue should be resolved by now BTW, in contrast to many other AV vendors MS usually is quite fast when it comes to handling reported false positives. A manual Windows update check should get you the latest Defender definitions.
Excluding the vorpX program folder is still a good idea, prevents potential similar issues with future updates.