Don't use Sonarr as ReleaseGroup if the pattern contains an advanced prefix/suffix.

src/NzbDrone.Core.Test/OrganizerTests/FileNameBuilderTests/FileNameBuilderFixture.cs

@@ -712,6 +712,18 @@ namespace NzbDrone.Core.Test.OrganizerTests.FileNameBuilderTests
                    .Should().Be("Sonarr");
         }
 
+        [TestCase("{Episode Title}{-Release Group}", "City Sushi")]
+        [TestCase("{Episode Title}{ Release Group}", "City Sushi")]
+        [TestCase("{Episode Title}{ [Release Group]}", "City Sushi")]
+        public void should_not_use_Sonarr_as_release_group_if_pattern_has_separator(string pattern, string expectedFileName)
+        {
+            _episodeFile.ReleaseGroup = null;
+            _namingConfig.StandardEpisodeFormat = pattern;
+
+            Subject.BuildFileName(new List<Episode> { _episode1 }, _series, _episodeFile)
+                   .Should().Be(expectedFileName);
+        }
+
         [TestCase("0SEC")]
         [TestCase("2HD")]
         [TestCase("IMMERSE")]

src/NzbDrone.Core/Organizer/FileNameBuilder.cs

@@ -425,7 +425,7 @@ namespace NzbDrone.Core.Organizer
         {
             tokenHandlers["{Original Title}"] = m => GetOriginalTitle(episodeFile);
             tokenHandlers["{Original Filename}"] = m => GetOriginalFileName(episodeFile);
-            tokenHandlers["{Release Group}"] = m => episodeFile.ReleaseGroup ?? "Sonarr";
+            tokenHandlers["{Release Group}"] = m => episodeFile.ReleaseGroup ?? m.DefaultValue("Sonarr");
         }
 
         private void AddQualityTokens(Dictionary<string, Func<TokenMatch, string>> tokenHandlers, Series series, EpisodeFile episodeFile)
@@ -759,6 +759,18 @@ namespace NzbDrone.Core.Organizer
         public string Suffix { get; set; }
         public string Token { get; set; }
         public string CustomFormat { get; set; }
+
+        public string DefaultValue(string defaultValue)
+        {
+            if (string.IsNullOrEmpty(Prefix) && string.IsNullOrEmpty(Suffix))
+            {
+                return defaultValue;
+            }
+            else
+            {
+                return string.Empty;
+            }
+        }
     }
 
     public enum MultiEpisodeStyle