Fixed: Make sure exactly one edition is monitored when using remote candidates

src/NzbDrone.Core/MediaFiles/BookImport/Identification/IdentificationService.cs

@@ -132,6 +132,7 @@ namespace NzbDrone.Core.MediaFiles.BookImport.Identification
 
             if (!candidateReleases.Any())
             {
+                _logger.Debug("No local candidates found, trying remote");
                 candidateReleases = _candidateService.GetRemoteCandidates(localBookRelease, idOverrides);
                 if (!config.AddNewAuthors)
                 {

src/NzbDrone.Core/MetadataSource/BookInfo/BookInfoProxy.cs

@@ -429,13 +429,25 @@ namespace NzbDrone.Core.MetadataSource.BookInfo
                 book.UseDbFieldsFrom(dbBook);
 
                 var editions = _editionService.GetEditionsByBook(dbBook.Id).ToDictionary(x => x.ForeignEditionId);
+
+                // If we have any database editions, exactly one will be monitored.
+                // So unmonitor all the found editions and let the UseDbFieldsFrom set
+                // the monitored status
                 foreach (var edition in book.Editions.Value)
                 {
+                    edition.Monitored = false;
                     if (editions.TryGetValue(edition.ForeignEditionId, out var dbEdition))
                     {
                         edition.UseDbFieldsFrom(dbEdition);
                     }
                 }
+
+                // Double check at least one edition is monitored
+                if (book.Editions.Value.Any() && !book.Editions.Value.Any(x => x.Monitored))
+                {
+                    var mostPopular = book.Editions.Value.OrderByDescending(x => x.Ratings.Popularity).First();
+                    mostPopular.Monitored = true;
+                }
             }
 
             var author = _authorService.FindById(authorId);