diff --git a/beetsplug/lastgenre/__init__.py b/beetsplug/lastgenre/__init__.py
index dacd72f93..557b063d5 100644
--- a/beetsplug/lastgenre/__init__.py
+++ b/beetsplug/lastgenre/__init__.py
@@ -316,12 +316,34 @@ class LastGenrePlugin(plugins.BeetsPlugin):
         are removed."""
         separator = self.config["separator"].get()
         if isinstance(obj, library.Item):
-            item_genre = obj.get("genre", with_album=False).split(separator)
+            genre_string = obj.get("genre", with_album=False)
         else:
-            item_genre = obj.get("genre").split(separator)
+            genre_string = obj.get("genre")
 
-        # Filter out empty strings
-        return [g for g in item_genre if g]
+        # Check if any separators are present before attempting to split
+        if separator in genre_string:
+            item_genre = genre_string.split(separator)
+        else:
+            # Check for alternative separators
+            split_separator = None
+            # Intentionally keep whitespace (trim later)
+            for alt_sep in [";", "/", ","]:
+                if alt_sep in genre_string:
+                    split_separator = alt_sep
+                    break
+
+            if split_separator:
+                item_genre = genre_string.split(split_separator)
+            else:
+                # No separators found, return an empty or single genre list
+                item_genre = [genre_string] if genre_string else []
+
+        # Filter out empty strings and strip whitespace
+        final_keep = [g.strip() for g in item_genre if g.strip()]
+        self._log.debug(
+            f"Existing genres gathered: {final_keep}"
+        )
+        return final_keep
 
     def _combine_resolve_and_log(
         self, old: list[str], new: list[str]
@@ -435,11 +457,20 @@ class LastGenrePlugin(plugins.BeetsPlugin):
                 ):
                     return result
 
-        # Nothing found, leave original if configured and valid.
+        # Nothing found, leave original (split up) genres if configured and valid.
+        if keep_genres and self.config["keep_existing"]:
+            resolved_keep = self._resolve_genres(keep_genres)
+            self._log.debug("Resolved keep genres: {}", resolved_keep)
+            return self._format_and_stringify(
+                resolved_keep
+            ), "original fallback (split and resolved)"
+
+        # Nothing found, leave original (single) genre if configured and valid.
         if obj.genre and self.config["keep_existing"]:
             if not self.whitelist or self._is_valid(obj.genre.lower()):
-                return obj.genre, "original fallback"
+                return obj.genre, "original fallback (as-is)"
 
+        self._log.debug("Pretend: No genre found. obj.genre is: {}", obj.genre)
         # Return fallback string.
         if fallback := self.config["fallback"].get():
             return fallback, "fallback"