Fixed: Already Imported check failing for some torrent releases

src/NzbDrone.Core.Test/DecisionEngineTests/AlreadyImportedSpecificationFixture.cs

@@ -128,6 +128,38 @@ namespace NzbDrone.Core.Test.DecisionEngineTests
             Subject.IsSatisfiedBy(_remoteEpisode, null).Accepted.Should().BeTrue();
         }
 
+        [Test]
+        public void should_be_accepted_if_grabbed_download_id_and_release_torrent_hash_is_unknown()
+        {
+            var downloadId = Guid.NewGuid().ToString().ToUpper();
+
+            GivenHistoryItem(downloadId, TITLE, _hdtv720p, HistoryEventType.Grabbed);
+            GivenHistoryItem(downloadId, TITLE, _hdtv1080p, HistoryEventType.DownloadFolderImported);
+
+            _remoteEpisode.Release = Builder<TorrentInfo>.CreateNew()
+                                                         .With(t => t.DownloadProtocol = DownloadProtocol.Torrent)
+                                                         .With(t => t.InfoHash = null)
+                                                         .Build();
+
+            Subject.IsSatisfiedBy(_remoteEpisode, null).Accepted.Should().BeTrue();
+        }
+
+        [Test]
+        public void should_be_accepted_if_grabbed_download_does_not_have_an_id()
+        {
+            var downloadId = Guid.NewGuid().ToString().ToUpper();
+
+            GivenHistoryItem(null, TITLE, _hdtv720p, HistoryEventType.Grabbed);
+            GivenHistoryItem(downloadId, TITLE, _hdtv1080p, HistoryEventType.DownloadFolderImported);
+
+            _remoteEpisode.Release = Builder<TorrentInfo>.CreateNew()
+                                                         .With(t => t.DownloadProtocol = DownloadProtocol.Torrent)
+                                                         .With(t => t.InfoHash = downloadId)
+                                                         .Build();
+
+            Subject.IsSatisfiedBy(_remoteEpisode, null).Accepted.Should().BeTrue();
+        }
+
         [Test]
         public void should_be_rejected_if_grabbed_download_id_matches_release_torrent_hash()
         {

src/NzbDrone.Core/DecisionEngine/Specifications/AlreadyImportedSpecification.cs

@@ -77,7 +77,7 @@ namespace NzbDrone.Core.DecisionEngine.Specifications
                 {
                     var torrentInfo = release as TorrentInfo;
 
-                    if (torrentInfo != null && torrentInfo.InfoHash.ToUpper() == lastGrabbed.DownloadId)
+                    if (torrentInfo?.InfoHash != null && torrentInfo.InfoHash.ToUpper() == lastGrabbed.DownloadId)
                     {
                         _logger.Debug("Has same torrent hash as a grabbed and imported release");
                         return Decision.Reject("Has same torrent hash as a grabbed and imported release");