diff --git a/beets/autotag/__init__.py b/beets/autotag/__init__.py
index ef775f6ec..b3cfa9541 100644
--- a/beets/autotag/__init__.py
+++ b/beets/autotag/__init__.py
@@ -97,8 +97,9 @@ def apply_metadata(album_info, mapping):
         if config['per_disc_numbering']:
             # We want to let the track number be zero, but if the medium index
             # is not provided we need to fall back to the overall index.
-            item.track = track_info.medium_index
-            if item.track is None:
+            if track_info.medium_index is not None:
+                item.track = track_info.medium_index
+            else:
                 item.track = track_info.index
             item.tracktotal = track_info.medium_total or len(album_info.tracks)
         else:
diff --git a/docs/changelog.rst b/docs/changelog.rst
index 7e51aabbc..6bf4a9681 100644
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -23,6 +23,9 @@ Fixes:
 * :doc:`/plugins/permissions`: Fix a regression in the previous release where
   the plugin would always fail to set permissions (and log a warning).
   :bug:`2089`
+* With :ref:`per_disc_numbering` enabled, some metadata sources (notably, the
+  :doc:`/plugins/beatport`) would not set the track number at all. This is
+  fixed. :bug:`2085`
 
 The last release, 1.3.19, also erroneously reported its version as "1.3.18"
 when you typed ``beet version``. This has been corrected.