Not sure - but this happened with every plug in - internal or 3rd party. I restarted Deluge on my seedbox and then the plug in installed correctly and seems to be working.

My torrents weren't extracting anymore and I saw that the "extractor" plugin somehow got unchecked. So I tried to reinstall it and when I clicked "install" the box unchecked. I tried downloading/installing a different extractor and got the same result. For some reason, they just ...