diff --git a/backend/app/plex/stream.py b/backend/app/plex/stream.py
index f404fac0..8727d1a3 100644
--- a/backend/app/plex/stream.py
+++ b/backend/app/plex/stream.py
@@ -667,9 +667,11 @@ def start_session(
         )
         respawned = _spawn(False, False, replace_only=s)
         if respawned is None:
-            # Superseded/culled mid-fallback — yield the session registered now (a newer seek-restart), or
-            # our own now-dead session if the key was cap-culled (its segment requests degrade to the
-            # route's retryable "not available yet", never a dishonest "file not found" from a None).
+            # Superseded/culled mid-fallback — yield whoever is registered now (a newer seek-restart), or
+            # our own now-dead session if the key was cap-culled. Never None here: the POST /session route
+            # turns a None return into a "Media file not found on disk" 404 — dishonest for a file that
+            # exists. A (dead) session instead degrades to a retryable 404 ("No active playback session" /
+            # "Not available yet") the client re-requests.
             return current_session(key) or s
         s = respawned
         ready = wait_for(_seg(0), timeout=25.0, proc=s.proc)